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					Data Quality Documentation:
Discharge Abstract Database
        2001–2002




        February 2003
Contents of this publication may be reproduced in whole
or in part provided the intended use is for non-commercial
purposes and full acknowledgement is given to the Canadian
Institute for Health Information.


Canadian Institute for Health Information
377 Dalhousie Street
Suite 200
Ottawa, Ontario
K1N 9N8

Telephone: (613) 241-7860
Fax: (613)241-8120
www.cihi.ca

 2003 Canadian Institute for Health Information
TM
     Registered Trade-mark of the Canadian Institute for Health Information
                                        Data Quality Documentation:
                                        Discharge Abstract Database
                                                2001–2002

Table of Contents
1.     Introduction..................................................................................................... 1
     1.1   An Overview of the DAD .............................................................................. 1
     1.2   Mandate..................................................................................................... 2
2.     Coverage ........................................................................................................ 4
     2.1   Population .................................................................................................. 4
     2.2   The DAD Frame........................................................................................... 4
     2.3   Frame Maintenance...................................................................................... 5
3.     Collection and Response ................................................................................... 6
     3.1   Data Collection............................................................................................ 6
     3.2   Data Elements............................................................................................. 8
     3.3   Data Quality Control .................................................................................... 8
     3.4   Response.................................................................................................. 10
4.     Revision History ............................................................................................. 13
     4.1   Major Changes for FY 2001–2002 .............................................................. 13
     4.2   Historical Changes ..................................................................................... 14
     4.3   Future Changes ......................................................................................... 15
     4.4   Historical References.................................................................................. 16
5.     Comparability ................................................................................................ 17
     5.1   Geography................................................................................................ 17
     5.2   Facility ..................................................................................................... 17
     5.3   Time ........................................................................................................ 18
     5.4   Person ..................................................................................................... 19
     5.5   External Source Validation .......................................................................... 19
6.     Summary of Data Limitations and Implications For Data Usage
       (FY 2001–2002)............................................................................................ 20
7.     References .................................................................................................... 24
8.     Contacts ....................................................................................................... 24
Appendix A......................................................................................................... A–1
Appendix B ......................................................................................................... B–1
                                                                   Data Quality Documentation:
                                                       Discharge Abstract Database 2001–2002



1. Introduction
An ongoing challenge for any organization producing statistical information is to ensure
that the quality of the information it produces is suited for its intended uses, and that data
users are provided with good information about data quality. To this end, the Canadian
Institute for Health Information (CIHI) has established a comprehensive and systematic
data quality program that includes the implementation and ongoing monitoring of a
corporate Data Quality Framework, as well as conducting special studies that focus on
data quality issues.

CIHI’s Data Quality Framework (DQF) was introduced to provide a common, objective
approach to assessing the data quality of all CIHI databases and registries. It also
standardizes information on data quality for users and helps to identify priority issues,
which in turn leads to continuous improvements. The DQF draws on Statistics Canada
guidelines and methods, Information Quality literature, CIHI’s mandate, as well as the
principle of Continuous Quality Improvement (CQI).

The framework is structured along five general dimensions of quality: accuracy, timeliness,
comparability, usability and relevance. These five dimensions are based on 24
characteristics, which in turn are based on 86 criteria. The framework implementation is
part of the larger quality cycle in which problems are identified, addressed, documented
and reviewed on a regular basis. A description of the Data Quality characteristics contained
in CIHI’s Data Quality Framework is available on CIHI’s web site.

This report, “Data Quality Documentation: Discharge Abstract Database, 2001–2002”, is
an important output of CIHI’s Data Quality Framework. It is intended to provide users with
information about the quality of the data contained in the database to help users decide
whether the information fits their needs. Beginning with this report, which is based on
fiscal year 2001 data, data quality documentation on the Discharge Abstract Database
(DAD) will be published annually with each release of the DAD. Updated documentation
will also be released as required. Users who require information beyond what is contained
in this report are encouraged to consult the reference section in this document or the DAD
program area at CIHI via <dad@cihi.ca>.

1.1 An Overview of the DAD
The DAD was originally developed in 1963 to collect data on hospital discharges in
Ontario. Over time, the mandate of the DAD has expanded in scope, as determined by
each Provincial and Territorial Ministry of Health. Currently, the DAD has almost national
coverage for acute inpatient care (excluding only Quebec and parts of Manitoba) and also
includes day surgery, chronic care, and rehabilitation episodes of care.

Over 4.2 million records are submitted to the DAD annually, with each record capturing a
standard clinical, demographic and administrative dataset on an episode-specific basis.
Inpatient records submitted to the DAD represent 75% of all inpatient discharges in
Canada. Historical DAD data are available beginning in fiscal year 1981. As acute care
facility participation has been staggered over time, data from 100% of acute care facilities



CIHI 2003                                                                                    1
Data Quality Documentation:
Discharge Abstract Database 2001–2002


in DAD participating provinces have been available since fiscal year 1998; however,
99.9% reporting was attained beginning in fiscal 1995 (only five smaller Prince Edward
Island facilities were not reporting).

Information from the Discharge Abstract Database is used by a variety of agencies and
facilities for planning, evaluation, research, and hospital funding. Hospitals also use the
data to support facility-specific utilization management decisions and administrative
research. Governments use the data for funding and system planning. Given these
important uses, the quality of data submitted to and produced from the DAD warrants
careful attention.

1.2 Mandate
The mandate of the DAD is to collect information on inpatient, day surgery, chronic care,
and rehabilitation events from facilities in participating provinces/territories. Provincial and
Territorial Ministries of Health mandate participation in the DAD. All Provinces and
Territories with the exclusion of Quebec and parts of Manitoba participate in the DAD.

The DAD is a core database at CIHI and information collected in the DAD is used in the
creation of parts of other databases including the Hospital Morbidity Database (HMDB), the
Hospital Mental Health Database (HMHDB), the National Trauma Registry (NTR), the
Ontario Trauma Registry (OTR) and the Therapeutic Abortions Database (TADB) (Figure 1).




2                                                                                      CIHI 2003
                                                                                                                                                   Data Quality Documentation:
                                                                                                                                       Discharge Abstract Database 2001–2002


                                                                  Discharge Abstract Database
                                                     Electronic data                                                                                                                                                                      Public
                                                    submissions and
                                                                                                                                                                                                        le
                                                       corrections                                                                                                                                  fiab
                                                                                                                                                                                                enti data
                                                     Paper corrections for                                                                                                                  n-id
                                                                                                                                          Prepare Public Reports                          No regate
                                                           MB,NB                                                                                                                           ag g
                                                                                                                                            Health Care in Canada
                                                                                                                                            Maclean's Health Report
                                                                                                                                            etc
                                                        Mainframe                                                                                                                                                                         Hospitals
                                                        processing                                                                                                                                                                        participating in
                                                                                                                                                                                                                                          DAD (excludes
                                                                                                                                                                                                                                          Manitoba hospitals
                                                                                                                                                                                                                                          outside Winnipeg and
                                                                                                                                                                                                                    le
                                                        Back-up on                                                                                                                                         tif   iab                      Quebec)
                                                                                                                                         Prepare Standard Reports                                       en
                                                          tapes                                                                                                                               n   -Id
                                                                                                                                            Expected Length of Stay (ELOS)                 No
                                                                                                                                            Resource Intensity Weight
                                                                                                                                            (RIW)TM
                                                                                                                                            Day Procedure Group (DPG)TM
                                                                                                                                            Error Correction Reports
                                                                                                                                            Comparison of hospital activity
                                                                                                                                            program (CHAPS, eCHAPS)
                                                                                                                                                                                                                                          Hospitals
                                                                                                                                            etc
                                                                                                                                                                                                                                          (participating in both
                                                                                                 Discharge Abstract
                                                              Coded summary                                                                                                                                                               DAD and the
                               Hospitals                                                              Database                                                                                                                            benchmarking study)




                                                                                                                                                                                                                                    ble
                                                        (no name or street address)
                             (BC, SK, MB- six                                                 Processes




                                                                                                                                                                                                                                 fia
                                                                                                                                                                                                                             nti
                            hospitals, ON, PE,
                                                                                                  Data quality checks                                            Prepare Special Reports




                                                                                                                                                                                                                           de
                             NB, NS, NF, YK,                                                                                                                          Annual Benchmarking




                                                                                                                                                                                                                       n-i
                                 NT, NU)                    Hospital specific data                and follow up with data




                                                                                                                                                                                                                     No
                                                                                                                                                                      Comparison of Canadian
                                                                                                  providers                                                           Hospitals
                                                                                                  Apply grouping                                                      (in collaboration with Haygroup
                                                                                                                                                                      Consulting Firm)                                                    Researchers
                               Hospitals                                                          methodologies                                                                                                                           Media
                                 AB                                                                                                                                                                                                       Private sector
                                                         Coded summary
                                                   (no name or street address)                                                                                                                                                            organizations
                                                                                                                                                                                                                                          Non-profit
                                                                                                                                                                                                       le                                 organizations
                                                                                                                                                                                                  fiab
                                                                                                                                                                                              enti
                                                                                                                                                                                          n-id
                              Ministry of                                                                                                        Review and                            No
                              Health, AB                                                                                                         prepare ad-                                                                              Researchers
                                                                                                                                                     hoc                                                                                  Hospitals
                                                                                                                                                  releases:
                                                                                      Hospital Morbidity             Hospital Mental             Aggregate                                                                                Researcher with
                                                                                         Database                    Health Database                 Data                                                  le                             consent
                                                                                                                                                                                                        iab
                                                                                        All provinces                 AB, ON, NB,                                                                  ntif
                                                                                                                                                                                              de                                          If required by
                                                                                       and territories                 NS, NF&L                                                           n-I
                                                                                                                                                                                        No                                                law
                                                                                                                                                 Review and                                     iable                                     Individuals
                                                                                                                                                 prepare ad-                             Identif
                                                                                                                                                                                                                                          requesting own
                                                                                                                                                     hoc                                                                                  data
                                                                                                                       Therapeutic                releases:
                                                                                       Ontario Trauma
                                                                                                                        Abortions                  Record
                                                                                                                        Database                 Level Data
                                                                                          Registry
                                                                                                                     SK, ON, NB, NS,
                                                                                                                                                                                                                                          Health Canada
                                                                                                                    NF&L, YT, NT, NU                                                                      d
                                                                                                                                                                                                     rypte                                Ontario data
                                                                                                                                                                                                 enc
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                                                                                                                                                                                      lth n        intact
                                                                                                                                                  Recurring                       Hea lth number                                          Care Ontario
                                                                                                                                                                                    Hea
                                                                                                                                                 record level                     Health number encrypted                                 Statistics
                                                                                                                                                 releases by                              Ident                                           Canada
                                                                                                                                                                                               ifiable
                                                                                                                     National Trauma              agreement                                                                               Ministries of
                                                                                                                         Registry
                                                                                                                                                                                                                                          Health
                                                                                                                                                                                                                                          (monthly, quarterly,
                                                                                                                                                                                                                                          annually

TM
     Registered Trade-mark of the Canadian Institute for Health Information                                                                                                                                                                                 Jan. 2003




Figure 1.                                 Discharge Abstract Database Data Flow Diagram




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Data Quality Documentation:
Discharge Abstract Database 2001–2002



2. Coverage
2.1 Population
The DAD includes all acute care hospital separations (discharges, deaths, sign-outs,
transfers) in participating provinces. Also found are same day surgery, chronic care,
rehabilitation and other data from across Canada. Rural hospitals in Manitoba and all
hospitals in Quebec are not currently included in the database. The DAD reports on a fiscal
year basis of discharge (April 1st to March 31).

In fiscal 2001–2002, 4,235,686 abstracts were submitted to the DAD. Inpatient acute
care accounted for 2,364,909 (56% of the records) while 1,811,794 (43%) were for day
surgery. A detailed breakdown of all discharges by province/territory and institution type is
summarized in Table 1.

Table 1.                   Summary of All Discharges for DAD 2001 by Province and Institution Type

            Acute/Active                   Day       Medical
                             Chronic                              Rehab     Others       Totals
             Treatment                   Surgery     Day Care
    NT            5,978            80       2,797                                         8,855
    NU            1,735                       551                                         2,286
    YK            2,838                     1,521                                         4,359
    NL           39,737          235       25,453                    115                 65,540
    PEI          17,544           15        3,358                                        20,917
    NS          102,766           11       96,797                 845           155     200,574
    NB          107,916        2,030       69,370        7,211    858           480     187,865
    ON        1,143,574        2,379    1,163,142              27,424         8,872   2,345,391
    MN           78,953                    65,252                                       144,205
    SK          139,828           72       93,326                             1,473     234,699
    AB          331,252          826                            1,095         2,648     335,821
    BC          392,788          748   290,227                  1,411                   685,174
    Total     2,364,909        6,396 1,811,794           7,211 31,748       13,628    4,235,686


2.2 The DAD Frame
A frame is a list of entities that supply data (i.e. whom you expect data from). The DAD
frame includes all acute care facilities in all provinces and territories with the exception of
parts of Manitoba and all of Quebec. Frame maintenance is controlled primarily by the
province/territory. All public (not-for-profit) acute care facilities are known and identified in
advance by the respective provinces/territories and are required to submit data on a yearly
basis. If data are not received from a particular institution, it is contacted by CIHI or if
necessary, the Provincial/Territorial Ministry of Health. It should be noted that although it is
not possible to determine whether an abstract was submitted for every episode of care,
mandates and legislation in place make it very unlikely that significant number of abstracts



4                                                                                       CIHI 2003
                                                                    Data Quality Documentation:
                                                        Discharge Abstract Database 2001–2002


would not be submitted (refer to Section 2.3 for more details on under-coverage). In
addition to acute care institutions, provinces/territories may also include rehabilitation and
chronic care centers, or day surgery (medical day care), or others, which are sometimes
required to submit to the DAD to enable a comprehensive repository of hospital activity for
that Province or Territory.

2.3 Frame Maintenance
The CIHI Management Report, produced monthly for provincial/territorial Ministries of
Health, provides summary information about all institutions that are required to send data
to DAD for a given fiscal year. Arranged by province/territory, it lists each institution by
number, name, city, number of abstracts submitted for each of the 12 (13 in British
Columbia) reporting periods and total number of abstracts submitted for the year.
Summary reports are also produced by region and abstract type.

Over-coverage within a frame results from including an entity (in this case a facility) more
than once in the database or including one that was not part of the intended frame. Under-
coverage occurs when an entity is on the frame but does not submit data.

With respect to the DAD, over-coverage is unlikely, as arrangements must be made for a
facility to submit data to the DAD, and abstract submissions by facility are closely
monitored by CIHI. Depending on the requirements of the user, however, exclusion criteria
may have to be applied in order to include the proper subset of records. For example, a
user may be interested in acute care institutions only and will therefore exclude chronic
care or rehabilitation cases that may also be contained in the database.

Under-coverage error within the DAD is low. Hospitals are mandated by their Provincial or
Territorial Ministry of Health to submit all abstracts in a fiscal year to the DAD. Also,
hospitals are bound by Provincial or Territorial legislation to maintain a health record for all
individuals seen in hospital, and in many provinces, hospital funding depends upon the
comprehensive submission of data for each patient by that hospital. As it is possible to
trend submissions by a hospital over time, significant declines in volume would be
followed-up by CIHI or the respective Provincial/Territorial Ministry of Health. One obvious
source of incomplete coverage is the absence of data from Quebec and parts of Manitoba.
An agreement has been reached with Manitoba for the entire province to be included in the
DAD for fiscal 2004; however, an agreement has not yet been reached with Quebec. With
regard to same day surgery, all provinces and territories submit this data with the
exception of Alberta, Quebec and parts of Manitoba.




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Data Quality Documentation:
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3. Collection and Response
3.1 Data Collection
The DAD data capture process and information flow is summarized in Figure 2.


                     Discharge Abstract Database
                           Information Flow
           Patient                                  Admission                Health            Discharge
                                                                             Record
             Flow
                              Patient
                                                              Diagnosis &                       Coding &
                                                             Interventions                     Abstracting
        Hospital
    Information                                                               Corrections      Abstract to
                                                    Review                                                    4-
           Flow                                                               Submitted           CIHI       425
                             Physician                                                                       days
                            Hospital-Specific
                                                        Corrections
    Information           Quarterly Reports - 37
                                                         Applied
                                                                               Reports to
                          days after last monthly                               Clients
        Flow at              reports are run

           CIHI                   Subsequent
                                                             Re-Edit
                                                                              Hosp.-spec.   1.5 -
                                   Reporting                                    Reports   10.0 days
    Note: Elapsed days
         are from end
                                  Comparative        Cut-off - 85 days       CMG™/DPG™
              of period                                                                          Editing
                                   Reporting         Distribution - 95 -
                                                                               RIW™
                                                         120 days




Figure 2.           Discharge Abstract Database Information Flow

Abstracting and Data Submission
The DAD Abstract is the record of hospital activity that is submitted to the DAD from each
facility. Each abstract is associated with a patient discharge and contains a list of the
relevant data elements to be submitted to the DAD for that patient. One individual person
can be associated with more than one abstract. Therefore, it should be recognized that the
total number of records contained in the DAD is not a reflection of patient volumes for
those provinces submitting to the DAD, but rather a reflection of hospital ‘activity’. One
version of the DAD abstract is for ICD-10-CA/CCI submissions and one version is for
ICD-9/CCP or ICD-9-CM submissions.

The DAD Abstracting Manual is the tool provided to clients, in either PDF or html format,
to guide them with the abstracting process of demographic, administrative, and clinical
data elements collected on each episode of care. Researchers and abstracting software
vendors also use the manual. The manual is divided into two sections: the core section



6                                                                                                                   CIHI 2003
                                                                   Data Quality Documentation:
                                                       Discharge Abstract Database 2001–2002


describing data submission requirements applicable at a national level and the provincial
variation section, which identifies Provincial/Territorial specific data elements. Depending
on Provincial or Territorial data submission requirements, the data elements are defined as
mandatory or optional. The manual contains for each data element, a data element
definition and corresponding codes. As well, applicable edits to the data element are
documented in the DAD manual. Refer to Appendix A for the key provincial abstracting
differences for the 2001 DAD.

Adherence to the data submission and coding standards described in the manual ensures
that CIHI reports accurately reflect the hospital’s patient activity. Adherence is enforced
through the application of edits and through educational sessions offered by CIHI. The core
manual with a provincial variations section is available through CIHI’s order desk on its
web site. One version is available for ICD-10-CA/CCI and one for ICD-9/CCP and
ICD-9-CM. This is the first time that CIHI has made the 2001 abstracting manual available
in electronic format.

Data Submission to CIHI’s data holdings including the Discharge Abstract Database is
facilitated through service packages called Core Plans. The Core Plan provides hospitals
access to CIHI’s national data holdings including services related to data quality and
processing, client support, access to data; national health information standards; selected
publications and reports; and basic education. Provincial and Territorial Ministries of Health
purchase these packages on behalf of their hospitals and mandate submission to various
CIHI databases (with the exception of Ontario and Manitoba where hospitals purchase
services directly from CIHI).

Diagnoses and Procedures
Classification systems in health care provide a standard mechanism for the capture and
coding of diagnoses and interventions. The International Statistical Classification of
Diseases and Related Health Problems—Tenth Revision was adopted by the World Health
Assembly in 1990. It is the most recent revision of an international classification system
used for classifying mortality and morbidity statistics.

ICD-10-CA is the enhanced Canadian version of the 10th revision of the International
Statistical Classification of Diseases and Related Health Problems. ICD-10-CA replaces the
earlier ICD-9 and ICD-9-CM classifications. CCI is the Canadian Classification of Health
Interventions, developed and maintained by CIHI. It contains a comprehensive list of
diagnostic, therapeutic, and support interventions. CCI replaces CCP and ICD-9-CM
intervention codes.

The initial version of the ICD-10-CA and CCI Coding Guidelines was released in 2001.
These guidelines are reviewed, amended and enhanced annually by a Pan-Canadian
Committee representing the provinces and territories. The 2002 Guidelines, of which there
are 178, are available in printable document format (pdf) on the CIHI web site and may be
downloaded free of charge.




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Data Quality Documentation:
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The 2001 DAD contains a mixture of data originally submitted to CIHI in one of three
classification schemes: ICD-10-CA/CCI, ICD-9/CCP, and ICD-9-CM. From east to west, the
following Provinces/Territories implemented ICD-10-CA/CCI in fiscal 2001: Newfoundland
and Labrador, Prince Edward Island, Nova Scotia, Saskatchewan (except for five facilities),
British Columbia, and Yukon Territory. In an effort to produce nationally comparable data in
the interim, CIHI created conversion tables that are used to map ICD-10-CA diagnosis and
CCI interventions back to ICD-9/CCP. In some cases, where a direct one-to-one conversion
was not possible, the conversion tables use a best "force fit" of diagnostic codes, and
comparability inevitably is compromised. Users who are analyzing specific diagnoses or
interventions over time are strongly advised to be prudent in their analytical approach by
first analyzing data in their original classification scheme (e.g. ICD-10-CA/CCI) before
utilizing the conversion tables.

3.2 Data Elements
Refinements and suggested enhancements to data elements in the DAD are communicated
to CIHI in several ways. These include:
(1)   routine communication from clients to DAD support services representatives
      (described in Section 3.3);
(2)   input from advisory committees; and
(3)   formal submissions for data element additions or deletions from stakeholders.

Once all of these suggestions for data element additions and enhancements are tallied from
each of the sources described above, annual meetings are organized by CIHI for its DAD-
Morbidity Steering Committee. The mandate of this committee is to discuss and make
recommendations to CIHI on operational or strategic issues related to the DAD and Morbidity
Databases. Each province or territory appoints a member to the committee, with a
requirement that the member possesses decision-making authority on matters related to the
DAD or Morbidity Databases in their Province or Territory. The committee considers whether
a proposed data element is appropriate for inclusion in the database and whether its
collection ought to be mandatory (to ensure national comparability), optional or a Provincial
variation (specific only to selected Provinces or Territories). It is through these processes that
new data elements appear in the DAD.

Section 4.1 describes the major changes to the DAD abstract implemented in fiscal 2001.

3.3 Data Quality Control
Quality control for the DAD is extensive and occurs at several different levels. Highlights
are provided below. For more detail, users are encouraged to refer to the document
“Quality Assurance Processes Applied to the Discharge Abstract and Hospital Morbidity
Databases”, available on the CIHI web site.

Support Services Representatives
CIHI has Support Services Representatives who have been assigned specific provinces/
territories and provide direct client support related to DAD products, assist in the



8                                                                                      CIHI 2003
                                                                      Data Quality Documentation:
                                                          Discharge Abstract Database 2001–2002


development and delivery of education programs, provide data quality expertise, and
build relationships with provincial/territorial data consultants, health organizations and
data users.

CIHI Education Program
Through the CIHI Education Program, instructional sessions are provided to clients on basic
abstracting, submission errors and corrections, CMGTM methodology, and report
interpretation. These sessions are one mechanism to ensure standardized coding practices
and adherence to CIHI’s data submission and collection requirements.

Abstracting Software and Role of External Software Developers (Vendors)
In order to standardize and ensure accurate data collection, CIHI’s respective data suppliers
hire external software vendors to install the necessary software infrastructure to enable
data submission and analysis. The abstracting software is developed according to CIHI
standards. Vendors submit test files to CIHI prior to installing their system at the client site
and receive support from CIHI for the interpretation of the standards. CIHI also provides
ongoing support in order to provide updates to specifications, identify issues and provide
feedback encountered during the transmission of data from client sites.

Systemic differences in vendor software exist although all vendors must meet CIHI
submission specifications. These differences could introduce errors in the data. For
example, a vendor may customize a client’s software to include data elements that may
not be part of the DAD data set. CIHI works with vendors to ensure compliance with DAD
terminology while respecting their proprietary freedom of software design.

CIHI Production System Edits and Correction Process
Approximately 700 data element edits are applied to the DAD. Errors detected by the edit
system are reported and the client is asked to submit the corrected abstract. The
correction and editing steps repeat until the client successfully corrects the abstracts or
the database closes as per its year-end deadline. Prior to the closure of the fiscal year,
clients can also submit additional abstracts if previously missing at the time of submission
of a period or delete duplicate abstracts when detected in subsequent analysis. Any
remaining hard errors are identified and CIHI imputes these with the standard default value
of “Z”‡ into the corresponding data element field. The percent of abstracts with errors
outstanding in the 2001 DAD is 1.2%.

Special Studies
CIHI is in the process of conducting a special DAD Data Quality Study to evaluate the
accuracy of coding in the DAD. The study involves returning to the original sources of
information (i.e. patient charts) and comparing this information with what exists in the CIHI
database. Specific health indicators, selected administrative clinical data, as well as an
assessment of the quality of coding for diagnoses and procedures are the focus of the

‡
 Hard errors may be denoted differently in the database depending on the variable type (e.g.
character, date, numeric) and on the version of the database.



CIHI 2003                                                                                      9
Data Quality Documentation:
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study. Two of the three years of the study have been completed and results are published
in “Discharge Abstract Database Data Quality Re-Abstraction Study—Combined Findings
for Fiscal Years 1999/2000 and 2000/2001”, which is available on the CIHI web site.

Also, CIHI is currently investigating the impact of ICD-10-CA/CCI implementation on CMG
grouper variables. CMG volume changes have been identified among provinces that have
implemented the new classification scheme. Detailed analyses are being conducted at the
CMG level, including the impact of shifts in CMG volume on RIWTM values. Details will be
made available as soon as our detailed analyses have been completed and resolutions
finalized.

3.4 Response

Unit Non-Response
Unit non-response is defined as an event not having been reported. This is also described
earlier in Frame Maintenance (Section 2.3). Hospitals are required to submit all abstracts
for each fiscal year to the DAD, as mandated by the Provincial and Territorial Ministries of
Health. In the 2001 DAD, there was one facility in Prince Edward Island that did not
submit any of its day surgery data prior to the year-end deadline. This facility will not
submit the outstanding data to CIHI. As a result, PEI day surgery volumes will be
considerably underreported in the 2001 DAD.

One health care corporation (7 institution numbers) in Newfoundland and Labrador
submitted acute, day surgery, and chronic care data for April, May, and June 2001 only.
CIHI has been notified that the outstanding data will be received by the end of March
2003. CIHI will re-open the DAD and revise accordingly.

Three additional facilities (altogether 7 institution numbers) in Newfoundland and Labrador
submitted the majority but not all abstracts (acute, day surgery, chronic care). There are no
plans for these outstanding data to be sent to CIHI; however, the impact is small on
Newfoundland case volumes.

No adjustments are made for unit non-response in the DAD. Current practice is to report
only on what data have been received, and to report any non-submitting facilities to the
respective Provincial/Territorial Ministry of Health.

Item Non-Response
Item non-response occurs when only part of the event was observed/recorded. The item
response rate for DAD depends largely on whether the data element is mandatory or
optional. No missing data are allowed for mandatory variables. If data are missing or
contain invalid values (hard errors), data are converted to 'Z'—these typically amount to
1.2% of all abstracts in the database. Examples of mandatory data elements for all
provinces include postal code (.03% had missing values or hard errors), birth date
(<.01%), admit date (<0.01%), and discharge date (<0.01%). Some variables (e.g.




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                                                                 Data Quality Documentation:
                                                     Discharge Abstract Database 2001–2002


procedure doctor service, wait time in emergency) are mandatory for certain provinces
only. For non-mandatory variables, the response rate is typically low. One example is wait
time in the Emergency Department (34% response).

No adjustments are made for unit non-response in the DAD. Current practice is to report
only on what data have been received, and to provide opportunity for abstract
correction/completion, although partial data is accepted by CIHI.

Response Bias
Response bias occurs when events are not accurately observed or reported properly and
the errors are not randomly distributed. For the DAD, the operating assumption is that
events are accurately recorded and captured in the abstract prior to data submission to
CIHI. There is no practical way to assess whether what actually transpired between
physician and patient is accurately reflected in the patient chart and the submitted DAD
abstract. However, one way to assess simple response bias in the coding of the
information in the abstract is through special studies called re-abstraction.

Given the size, coverage and importance of the Discharge Abstract Database, CIHI’s first
special re-abstraction study is of the DAD. The DAD Data Quality Study is a national study
that uses a statistical sampling methodology to reliably measure the accuracy of the coding
of selected non-medical and clinical administrative data contained in the DAD, as well as
assess the quality of coding for diagnoses and procedures. CIHI Classification Specialists
return to the original patient charts and compare this information with what exists in the
DAD. The study represents an important step towards making improvements to health
information by identifying potential enhancements to the DAD and CIHI’s coding
guidelines/standards. A detailed description of the study methodology and findings is
available on CIHI’s web site.

In short, the study assessed the percentage of times that CIHI coders disagreed with the
codes submitted to the DAD when re-abstracting the same information from the original
chart. The frequency of discrepancies and the associated reasons for the discrepancy were
recorded. The DAD Data Quality Re-Abstraction Study reports that many mandatory
demographic and non-medical data elements had a discrepancy rate of less than 1%.
However, three data elements had discrepancy rates between 1 and 5%: Institution To,
Institution From and Admit Hour. Discrepancies for Admission Category occurred 15.5% of
the time and for Discharge Hour, 10% of the time. Of the various reasons for these
discrepancies, the top three were: original coder missing information that was documented
on the chart, inconsistent or conflicting information, and discrepancies between the patient
chart and data in the hospital admitting/discharge information system.

Reliability
Despite considerable data documentation, educational training, and other support for
coders, the DAD Data Quality Re-Abstraction Study identified coding discrepancies among
diagnoses and procedures (discrepancy displayed as percent):




CIHI 2003                                                                                  11
Data Quality Documentation:
Discharge Abstract Database 2001–2002


•    Most Responsible Diagnosis—12.8% (different selection of MRDx code or coded as
     different type)
•    Comorbid Condition Diagnosis Typing—15.5%
•    Comorbid Condition Diagnosis—23.2%
•    Any diagnosis different—6.0% (includes MRDx or Comorbid Condition)
•    E-code—10.2% (results based on year two of study only)
•    Principal Procedure—7.0%
•    Procedure code different—4.9%
•    Other Procedures—19.7%

In some cases, it was found that a small proportion of facilities with unusually high
discrepancy rates was contributing substantially to the national estimates. Also, some
findings were not similar from year one compared to year two of the Study. Top reasons
for the discrepancies included: the re-abstractor disagreeing that the diagnosis significantly
impacted on the treatment and/or length of stay, different interpretations of the
documentation, the original coder missing information that was documented on the chart,
or the original coder not properly following the code book.




12                                                                                  CIHI 2003
                                                                    Data Quality Documentation:
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4. Revision History
Typically, the DAD is not revised after the fiscal year end closure. Errors detected after the
database is closed generally are not corrected since they tend to be relatively insignificant.
A few exceptions were made for the 2001 DAD, due to obstacles encountered as part of
the first year of ICD-10-CA/CCI implementation in Canada.

A one-time extension has been granted to permit ICD-10-CA/CCI submitting provinces to
send corrections to CIHI by March 28, 2003. A one-time extension until the end of March
2003 has also been granted to accommodate outstanding data from the health care
corporation in Newfoundland and Labrador (spanning seven institution numbers) that had
submitted only three periods (months) of data for acute, day surgery, and chronic care
data. Therefore, although DAD 2001 data are currently available, these data are subject to
change until the final updates are made and available in April 2003.

The DAD was re-opened in January 2003 to correct errors discovered after the closure of
the DAD: one British Columbia facility’s discharge disposition values for day surgery cases
and Manitoba institution transfer to/from types (see Section 6 for more details). In
February 2003, the DAD was also revised to correct errors in the assignment of institution
type among three generic Alberta institution transfer to/from codes (see Section 6). DAD
2001 data released prior to these time periods may contain these errors.

4.1 Major Changes for FY 2001–2002
Redevelopment of DAD ICD-10-CA/CCI Abstract
The DAD abstract was re-developed in order to:
•   accommodate the ICD-10-CA/CCI classification system
•   improve comparability of data through increased inter-provincial standardization
•   improve definitions and facilitate linkages among databases and registries
•   add new data elements
•   delete data elements which are no longer relevant

Client input was used to produce the revised DAD by assessing options against four
criteria: feasibility, utility, scope, and positive interdependencies vis-à-vis other CIHI
databases and registries. Lists and descriptions of the new, modified, and deleted data
elements are shown in Appendix B. For more information, users should consult the
“DAD/Morbidity Database Redevelopment Project: New Abstract, Draft Interim Progress
Report” available on the CIHI web site.

For fiscal year 2001–2002, the revised DAD was implemented in five provinces and one
territory, regions implementing ICD-10-CA/CCI.




CIHI 2003                                                                                    13
Data Quality Documentation:
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Electronic Submission
DAD participating provinces and territories have been shifting from paper-based to
electronic abstract submissions. Beginning with the 2001 DAD, all participating facilities
are now submitting to CIHI in electronic format.

Wait Time in ER
Ontario, New Brunswick, Nova Scotia, and Newfoundland currently mandate the collection
of data elements related to waiting time in the Emergency Department prior to being
admitted as an inpatient. For the DAD data elements needed to obtain a patient’s ‘Wait
Time in ER’, “data not available” was a valid code in the DAD FY 2000, became an invalid
code in FY 2001 for abstracts submitted in the ICD-10-CA/CCI format, then when it
became obvious that many hospitals were unable to provide their information accurately,
reverted back to become a valid code for FY 2003. Given these changes and varying
reporting requirements among provinces/territories, users should exercise caution when
analyzing ‘Wait Time in ER’ over time or across Canada.

4.2 Historical Changes
Health Care Number
The collection and provision of provincial/territorial health care numbers in the DAD have
been an evolving process. Health care number is mandatory for submission in all DAD
participating provinces with the exception of Manitoba, where submission is optional. CIHI
validates this field against either files or algorithms provided by each Ministry of Health.
Beginning with the 1999 DAD, allowance was made to capture instances in which the
patient was insured by another province's health plan. In such cases, CIHI can only
validate the length of the data field, not the actual number. In the past, British Columbia,
Alberta, Ontario, and the Northwest Territories have revised their health care numbering
systems (e.g. from family to individual-based) and have issued new health care numbers.
However, the DAD database does not contain the linking information between the old and
the new numbering systems. Therefore, users must exercise caution when using health
card number for linkage purposes. Note that CIHI only releases encrypted health card
numbers to external users under its Privacy and Confidentiality Policy.

Institution Number
Institution Number is not standardized across time. Institution types and numbers have
changed over the years because of closures and mergers. The same institution can have
different institution numbers for different levels of care. Our experience has shown that
longitudinal records of institution number changes are well maintained in some
Provinces/Territories and not in others. Accurately managing institution numbers over time
is challenging. Currently, a national frame is being developed by CIHI in order to track
changes in institution numbers due to mergers, closures, and openings. Therefore, linkages
by institution number over time are only advisable for small samples of hospitals until a
national frame of institution number changes is completed. Note that release of
unencrypted institution numbers requires approval by CIHI’s Privacy, Confidentiality and
Security team.


14                                                                                 CIHI 2003
                                                                  Data Quality Documentation:
                                                      Discharge Abstract Database 2001–2002


Level of Care
Provincial participation and facility participation in the DAD has been staggered over time.
Complete (100%) reporting by all acute care facilities in Canada (with the exception of
Quebec and parts of Manitoba) was attained beginning in fiscal 1998; however, 99.9%
reporting was attained beginning in fiscal 1995 (only five smaller Prince Edward Island
facilities were not reporting).

Day surgery data have been submitted consistently since the early 1990’s; however, as of
fiscal 1997, Alberta ceased to provide day surgery data to the DAD. Effective fiscal 2003,
Ontario will no longer provide day surgery data to the DAD; instead it will report this
information to CIHI’s National Ambulatory Care Reporting System. A task force was
established to assess the implications of this shift for reporting and case mix grouping
methodologies and is expected to complete a final report by Spring 2003. Once published,
it will be available on both CIHI’s and the Ontario Ministry of Health and Long-Term Care’s
web sites.

International Facilities
There are no explicit exclusion criteria for the DAD. Even facilities from foreign countries
may submit data to DAD under certain arrangements. The 2001 DAD does not contain
data from international facilities. However, from fiscal 1992–1993 to 2000–2001,
Bermuda facilities submitted to the DAD. Users therefore must apply appropriate exclusion
criteria when conducting national analyses prior to fiscal 2001.

4.3 Future Changes
Further ICD-10-CA/CCI Implementation
The following provinces/territories will submit abstracts in ICD-10-CA/CCI in the 2002
DAD: Alberta, five remaining facilities in Saskatchewan, Ontario, Northwest Territory, and
Nunavut Territory. New Brunswick will implement ICD-10-CA/CCI in 2003 and Manitoba in
2004. Quebec is not currently a DAD participating province.

Redevelopment of Complexity Overlay
In September 2002, CIHI’s data quality study and collaborative work with the Ontario
Ministry of Health and Long-term Care and its Joint Policy and Planning Committee (JPPC)
analyzed the impact of variations in coding practices on Complexity Overlay or PlxTM.
Jointly, the conclusion was that these variations made the use of Complexity Overlay
unreliable for hospital funding and for many efficiency comparisons. The issues are limited
to efficiency products that use this one tool and do not compromise the overall utility of
CIHI’s pan-Canadian statistics and reports that continue to serve as vital tools for
consumers of health information. CIHI is currently investigating options for redeveloping
Complexity Overlay.

A final report on CIHI’s special study on the consistency of coding practices and
effectiveness of coding standards will soon be available and will be posted on the CIHI
web site.


CIHI 2003                                                                                  15
Data Quality Documentation:
Discharge Abstract Database 2001–2002


4.4 Historical References
The following DAD-related products are updated regularly. Users should consider both the
fiscal year and classification scheme when referring to DAD documentation.
•    DAD Abstracting Core Manual (ICD-10-CA, and ICD-9 or ICD-9-CM available)
•    DAD Abstracting Provincial/Territorial Variations (ICD-10-CA, and ICD-9 or ICD-9-CM
     available)
•    CMG/Plx Directory (ICD-10-CA, and ICD-9 or ICD-9-CM available)
•    DAD Resource Intensity Weights and Expected Length of Stay
•    Day Procedure Groups (CCI, ICD-9-CM or CCP available)




16                                                                               CIHI 2003
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5. Comparability
Comparability refers to the extent to which a database can be properly integrated within
the entire health information system at CIHI. The DAD includes detailed information on all
hospital discharges in Canada (with the exception of Quebec and parts of Manitoba).
Consequently, it is the prime resource to investigate issues regarding acute care and
hospital activity. The DAD is also a data source for the following CIHI databases: Hospital
Morbidity Database, Hospital Mental Health Database, National Trauma Registry, Ontario
Trauma Registry and the Therapeutic Abortions Database.

In performing analyses over time or across provinces/territories, users should note that in
any given fiscal year, some data elements were mandatory or optional nationally or for
specific provinces/territories. A single document is not currently available that would
identify the changing status of these data elements over time. However, a special initiative
is currently underway to retrospectively document when data elements were introduced
and endorsed by the province/territory, and whether these elements were mandatory or
optional for data collection. It is possible to track changes by examining the yearly
documentation that is produced (e.g. abstracting manuals). DAD support staff are also
available to answer questions about year over year data element changes.

5.1 Geography
In addition to residence code, postal code is a common variable on almost all CIHI
databases. Along with the PCCF (Postal Code Conversion File), any standard geographical
classification can be obtained, making it possible to compare with other databases. The
forward sortation area (i.e. first three digits of a postal code) is typically the lowest level of
aggregation normally available to external users under CIHI’s Privacy and Confidentiality
Policy. The release of information for small geographical areas may also be restricted to
assure confidentiality. Special requests require approval by the CIHI Privacy,
Confidentiality, and Security Team. Note that for some rural areas, postal code data do not
necessarily provide an accurate picture of patient residence because of the use of P.O. Box
numbers, which may be located in a region different from the place of residence. Also,
rural postal codes may map to more than one enumeration area, thus reducing the ability
to determine the specific place of residence.

5.2 Facility
The institution code in the DAD uses a 4-digit provincial institution number with a
provincial prefix resulting in a unique code across Canada. This is either the same or very
similar to the codes used in other CIHI databases. Requests for institution-identifying
information require approval by the CIHI Privacy, Confidentiality, and Security Team. For
limitations related to institution number, see Section 4.2.




CIHI 2003                                                                                      17
Data Quality Documentation:
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5.3 Time
Although DAD data are collected on the basis of fiscal year of discharge, the range of date
variables in the DAD (e.g. admission date, discharge date) allows the user to examine any
time frame desired. This flexibility is especially useful in comparison with registries, which
tend to be cumulative rather than separate databases for discrete years.

With regard to DAD data submission processes over time, there is some variation across
provinces and territories (Table 2). All data must be submitted prior to the year-end
deadline, typically July 15.

Table 2.      Provincial Policies for DAD Data Submission

 Province             Existing Data Submission Policy
 NWT                  None; CIHI policy followed
 Nunavut              None; CIHI policy followed
 Yukon                None; CIHI policy followed
 Nfld and Labrador    3 months post year-end (June 30)
 PEI                  None; CIHI policy followed
 NS                   30 days after month-end
 NB                   None; CIHI policy followed
 Ontario              3 months post year-end (June 30)
 Manitoba             None; CIHI policy followed
 Sask                 60 days after month-end
 Alberta              90 days after month-end
 BC                   None; CIHI policy followed
 CIHI                 DAD year-end deadline for data submissions and corrections is
                      typically July 15. The release date is typically September 30.
                      Extensions were granted for fiscal 2001 to accommodate
                      implementation of ICD-10-CA/CCI.

Efforts to improve the timeliness of DAD data have been a long-standing operational
priority for CIHI. In 1999, a national survey was conducted with the objective of examining
the data collection and submission processes in hospitals to determine what variation
exists in practices such as documentation and coding required to complete the DAD
abstract. Other objectives of the survey were to identify best practices in the timely
submission of data and, based on the results, to initiate a nationally oriented change
process in data submission and reporting. For a detailed review of these findings, users
should refer to the document “Improving Timeliness of the Discharge Abstract Database
Data” on the CIHI web site.




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                                                                   Data Quality Documentation:
                                                       Discharge Abstract Database 2001–2002


5.4 Person
Discharges associated with the same individual can be identified by the encrypted health
care number. Refer to Historical Changes (Section 4.2) for limitations regarding health care
number. This is the standard person identifier and is common on most other CIHI
databases. It is also possible to conduct a probabilistic linkage using person identifiers such
as sex, birth date, postal code, admission and procedure dates. However, birth date and
full postal code are not normally made available to external users. Access to restricted data
elements as well as the use of DAD data for data linkage studies require prior approval by
the CIHI Privacy, Confidentiality, and Security Team. Users should note that patient names
and street addresses are not part of the DAD database.

5.5 External Source Validation
Ministries of Health validate CIHI’s number of acute care discharges against Hospital
Census reports, which are sent by the facilities to the respective Ministries of Health.




CIHI 2003                                                                                   19
Data Quality Documentation:
Discharge Abstract Database 2001–2002



6. Summary of Data Limitations and Implications
   For Data Usage (FY 2001–2002)
•    The DAD includes hospital inpatient data from all acute care hospitals with the
     exception of parts of Manitoba and all of Quebec. CIHI does not impute information in
     the DAD to compensate for Quebec and Manitoba. However, national inpatient data are
     available through the Morbidity database, which is derived from the DAD and is also
     managed by CIHI.

•    Although DAD 2001 data are currently available to users, data are subject to change
     until the final updates are made and available in April 2003. A one-time extension has
     been granted to permit ICD-10-CA/CCI submitting provinces to send corrections to CIHI
     by March 28, 2003. A one-time extension until the end of March 2003 has also been
     granted to accommodate outstanding data from the health care corporation in
     Newfoundland and Labrador (spanning seven institution numbers) that had submitted
     only three periods (months) of data for acute, day surgery, and chronic care data.

•    With regard to day surgery data collected in the DAD, all DAD participating provinces
     and territories, with the exception of Alberta, submit day surgery data. Manitoba
     submits only 40% of its day surgery cases to the DAD.

•    The submission of Ontario day surgery data is mandatory for qualifying procedures and
     optional for non-qualifying procedures. Examples of non-qualifying procedures are
     angiocardiography and proctosigmoidoscopy. Ontario will cease reporting day surgery
     data to the DAD at the end of fiscal 2002. Beginning in fiscal 2003, Ontario will report
     day surgery data to CIHI’s National Ambulatory Care Reporting System.

•    One facility in Prince Edward Island did not submit any of its day surgery data prior to
     the 2001 year-end deadline. This facility will not submit outstanding data to CIHI. As a
     result, PEI day surgery volumes are considerably underreported in the 2001 DAD.

•    Three additional facilities (altogether seven institution numbers) in Newfoundland
     submitted the majority, but not all abstracts (acute care, day surgery, chronic care).
     There are no plans for these outstanding data to be sent to CIHI; however, the impact
     is small on Newfoundland case volumes.

•    With regard to non-acute care data collected in the DAD, the comprehensiveness of the
     data varies by province/territory. In Ontario, some chronic care data are sent to the
     DAD in addition to the Ontario Chronic Care Patient System, a database also managed
     at CIHI. Data submitted to DAD under institution numbers corresponding to free
     standing psychiatric facilities and Veteran Affairs Canada are regrouped under “Other”
     in the DAD for CIHI reporting purposes. Users of the data should be aware that the
     comprehensiveness and requirements for collection of data from non-acute institutions
     via the DAD vary over time and institution types change across years. For specific
     details of these changes, contact CIHI.




20                                                                                  CIHI 2003
                                                                       Data Quality Documentation:
                                                           Discharge Abstract Database 2001–2002


•   Since the 2001 DAD contains a mixture of data originally submitted to CIHI in one of
    three classification schemes (ICD-10-CA/CCI, ICD-9/CCP, and ICD-9-CM), users are
    strongly advised to analyze data using the original classification scheme first before
    using CIHI conversion tables. From east to west, the following Provinces/Territories
    implemented ICD-10-CA/CCI in fiscal 2001: Newfoundland and Labrador, Prince
    Edward Island, Nova Scotia, Saskatchewan (except for five facilities), British Columbia,
    and Yukon Territory. In an effort to produce nationally comparable data in the interim,
    CIHI produced conversion tables to standardize ICD-10-CA diagnosis and CCI
    interventions back to ICD-9/CCP. In cases in which a direct one-to-one conversion was
    not possible, the conversion tables use a best "force fit" of diagnostic codes, and
    comparability inevitably is compromised.

•   The collection of a DAD data element within a province/territory can be mandatory or
    optional or specific to that region, the decision made by each individual
    Provincial/Territorial Ministry of Health. Response rates are typically low for non-
    mandatory fields. For instance, special care unit information was optional to collect in
    Ontario in 2001. Users should be aware of these data element variations when
    conducting data analyses. Refer to Appendix A for the key provincial abstracting
    differences for the 2001 DAD or consult the DAD Abstracting Manual for full details on
    each DAD data element, including provincial variations. Appendix B lists the new,
    modified, and deleted data elements on the redeveloped 2001 DAD abstract,
    implemented in ICD-10-CA/CCI provinces/territories.

•   For acute care cases, recent analyses by CIHI show that coding variations exist in the
    DAD. These variations are related to ICD-10-CA, ICD-9, ICD-9-CM diagnosis codes
    defined as Type 1* and Type 2†, which impact how a patient is defined in terms of
    clinical complexity. Such variations have made the use of Complexity Overlay unreliable
    for hospital funding and for many efficiency comparisons. CIHI is currently investigating
    options for redeveloping Complexity Overlay. Refer to Future Changes (Section 4.3) for
    further detail.

•   CIHI is currently investigating the impact of ICD-10-CA/CCI implementation on CMG
    grouper variables. CMG volume changes have been identified among provinces that
    have implemented the new classification scheme. Detailed analyses are being
    conducted at the CMG level, including the impact of shifts in CMG volume on RIW
    values. Details will be made available as soon as our detailed analyses have been
    completed and resolutions finalized.




*
  Type 1 Diagnosis, or Pre-Admit Comorbidity, is a co-existing condition present prior to admission
that has a significant influence on the patient’s length of stay or significantly influences the
management/treatment of the patient while in hospital.
†
  Type 2 Diagnosis, or Post-Admit Comorbidity, is a condition arising during the hospital observation
or treatment that has a significant influence on the patient’s length of stay or significantly
influences the management/treatment of the patient while in hospital.


CIHI 2003                                                                                         21
Data Quality Documentation:
Discharge Abstract Database 2001–2002


•    Provincial standards, edits, and procedures regarding health card number have changed
     over the years. Therefore, users must exercise caution when using health card number
     for linkage purposes. Refer to Historical Changes (Section 4.2) for more detail. Note
     that CIHI only releases encrypted health card numbers to external users under its
     Privacy and Confidentiality Policy.

•    Note that for some rural areas, postal code data do not necessarily provide an accurate
     picture of patient residence. Rural residents may use P.O. Box numbers, which may be
     located in a region different from the place of residence. Also, rural postal codes may
     map to more than one enumeration area, thus reducing the ability to accurately
     determine place of residence. The forward sortation area (first 3 digits of postal code)
     is typically the lowest level of aggregation available to external users under CIHI’s
     Privacy and Confidentiality Policy. The release of information for small geographical
     areas may also be restricted to assure confidentiality.

•    The release of institution number is also restricted under CIHI’s Privacy and
     Confidentiality Policy. It is typically available to external users in encrypted form only.
     Special requests for unencrypted institution numbers require approval by the CIHI
     Privacy, Confidentiality and Security Team.

•    Wait-time in emergency may be underestimated for some facilities due to the difficulty
     in collecting the exact decision to admit time. When the exact decision to admit time is
     not available, admit time is used as a proxy. This may inaccurately reflect wait times
     for some provinces. Also, users should exercise caution when analyzing ‘Wait Time in
     ER’ over time, given historical changes in wait time data elements and varying reporting
     requirements among provinces/territories (see Major Changes, Section 4.1).

•    Day surgery cases discharged from one institution in British Columbia in the 2001 DAD
     were erroneously coded as signed out against medical advice (discharge disposition=6)
     instead of discharged home (discharge disposition=5). This was due to faulty software
     programming at the hospital site, affecting 9,005 abstracts (3% of BC day surgery
     volume). The DAD was revised in January 2003 to correct this error by recoding all
     sign-outs to discharges home. However, 2001 DAD data released prior to January may
     still contain this error.

•    The 2001 DAD database was revised in January 2003 to correct erroneous
     assignments of institution type among Manitoba institution transfers (to/from). Some
     non-acute transfers were coded as acute in the DAD database, therefore overestimating
     RIW values for Manitoba cases. 2001 DAD data released prior to January may still
     contain this error.

•    The 2001 DAD database was revised in February 2003 to correct erroneous
     assignment of institution type to Alberta generic codes #89996 (Unclassified), #89997
     (Home Care Facility), #89998 (Home for the Aged) in the 'Institution transfer to' or
     'Institution transfer from' fields. Some of these non-acute transfers were coded as
     acute, therefore possibly overestimating some RIW values. Although now corrected,
     data released prior to February may still contain errors.



22                                                                                      CIHI 2003
                                                                    Data Quality Documentation:
                                                        Discharge Abstract Database 2001–2002


•   According to coding guidelines, the submitting (reporting) institution number of the
    abstract should not appear in either the 'Institution From' or 'Institution To' field of that
    abstract. However, an analysis of the 2001 DAD showed that 8,514 abstracts (99% of
    which are from Ontario) contained this error. CIHI has implemented this edit check for
    the 2002 DAD. As the affected abstracts comprise <1% of all 2001 DAD abstracts
    and <1% of all Ontario abstracts, the impact on users is minimal.

•   Admission/discharge times in the ICD-10-CA/CCI provinces and one territory are
    captured in hours and minutes. The other provinces/territories report times as rounded
    up to hours, with minutes presented as ‘00’ in the database. Users may wish to
    standardize the format of these fields when conducting national analyses using the FY
    2001–2002 data.




CIHI 2003                                                                                     23
Data Quality Documentation:
Discharge Abstract Database 2001–2002



7. References
Canadian Institute for Health Information, “DAD Abstracting Core Manual”
(ICD-10-CA/CCI, and ICD-9/ICD-9-CM available), www.cihi.ca

Canadian Institute for Health Information, “DAD Abstracting Provincial/Territorial
Variations” (ICD-10-CA/CCI, and ICD-9/ICD-9-CM available), www.cihi.ca

Canadian Institute for Health Information (2000), “Improving Timeliness of the Discharge
Abstract Database Data”, www.cihi.ca

Canadian Institute for Health Information (2000), “Discharge Abstract Database
(DAD)/Morbidity Database Redevelopment Project: New Abstract. Draft Interim Progress
Report”, www.cihi.ca

Canadian Institute for Health Information (2002), “Discharge Abstract Database Data
Quality Study, Preliminary Year 1 Findings”, www.cihi.ca

Canadian Institute for Health Information (2002), “Discharge Abstract Database Data
Quality Re-Abstraction Study: Combined Findings for Fiscal Years 1999/2000 and
2000/2001”, www.cihi.ca

Canadian Institute for Health Information (2002), “Quality Assurance Processes Applied to
the Discharge Abstract and Hospital Morbidity Databases”, www.cihi.ca



8. Contacts
For more information, please contact dad@cihi.ca




24                                                                                   CIHI 2003
             Appendix A

Key Provincial Abstracting Differences
             2001–2002

       ICD-10-CA/CCI Layout
  ICD-9/CCP and ICD-9-CM Layout
                                                                                Data Quality Documentation:
                                                                    Discharge Abstract Database 2001–2002


                      Key Provincial Abstracting Differences, Fiscal 2001–2002
               For Provinces Adopting New DAD Abstract and ICD-10-CA/CCI Coding:
                                    NL, PE, NS, SK (part), BC, YK
                                         Inpatient Discharges

 Legend
 M:                     Mandatory data element
 M*:                    Mandatory data element with a provincial variation
 Blank:                 Optional data element
 Gray Shading:          Province does not submit in ICD-10 Layout
 Black Shading:         Province does not submit to the DAD


Group & Field No.                      Data Element   NL   PE   NS    NB   QC   ON   MB   SK   AB   BC   NT   YK    NU

     01 01          Institution Number                M    M    M                         M         M         M
     01 03          Batch Year                        M    M    M                         M         M         M
     01 04          Batch Period                      M    M    M                         M         M         M
     01 05          Batch Number                      M    M    M                         M         M         M
     01 06          Abstract Number                   M    M    M                         M         M         M
     01 08          Coder Number                      M    M    M                         M         M         M
     01 09          Chart Number                      M    M    M                         M         M         M
     01 10          Register Number                   M         M                                             M
     01 11          Second Chart/Register Number                                          M
     01 12          Maternal/Newborn Chart/Reg #      M    M    M                                   M         M
     03 01          Health Care Number                M    M*   M*                        M*        M*        M*
     03 02          Postal Code                       M    M    M                         M         M         M
     03 03          Residence Code                    M         M
     03 04          Gender                            M    M    M                         M         M         M
     03 05          Prov/Terr Issuing HCN             M    M    M                         M         M         M
     03 06          RFP                               M    M    M                         M         M         M
     03 08          Birthdate                         M    M    M                         M         M         M
     03 09          Estimated Birthdate               M    M    M                         M         M         M
    03 11-27        Prov/Terr Ancillary Data                    M*                        M*        M*
     04 01          Admit Date                        M    M    M                         M         M         M
     04 02          Admit Hour                        M    M    M                         M         M         M
     04 04          Institution From                  M*   M*   M*                        M*        M*        M*
     04 05          Admit Category                    M    M    M*                        M*        M*        M
     04 06          Entry Code                             M    M*                        M         M         M
     04 07          Admit by Ambulance                M         M                                   M         M
     04 08          Readmission Code                  M    M    M                                   M
     04 11          ER Decision to Admit Date         M         M
     04 12          ER Decision to Admit Time         M         M




CIHI 2003                                                                                                     A–1
Data Quality Documentation:
Discharge Abstract Database 2001–2002


Group & Field No.                      Data Element         NL   PE   NS   NB   QC   ON   MB   SK   AB   BC    NT   YK   NU

      04 13         Date Patient Left ER                    M         M
      04 14         Time Patient Left ER                    M         M
      05 01         Discharge Date                          M         M                        M         M          M
      05 02         Discharge Hour                          M         M                        M         M          M
      05 04         Institution To                          M*   M*   M*                       M*        M*         M*
      05 05         Discharge Disposition                   M    M    M                        M         M          M
      07 01         Main Patient Service                    M*   M    M*                       M*        M*         M*
      07 02         Sub-service                                       M*
      07 03         Weight (0-29 days on admission)         M    M    M                        M         M          M
      07 04         Abstract Overflow
      08 01         Service Transfer (3 occurrences)                                           M         M*
      08 01         Alternate Level of Care (ALC)           M    M    M                        M         M          M
      08 02         Sub-service                                                                M
      08 03         Service Transfer Days                                                      M         M          M
      09 01         Provider Type (8 occurrences)           M    M*   M                        M*        M          M
      09 02         Provider Number                         M    M    M                        M         M*         M
      09 03         Provider Service                        M    M    M                        M         M          M
      10 01         Diagnosis Prefix (25 occurrences)                                          M
      10 02         Diagnosis Code (ICD-10-CA)              M    M    M                        M         M          M
      10 04         Diagnosis Type                          M    M*   M*                       M         M          M
      10 05         Cancer Staging – Clinical Tumour
      10 06         Cancer Staging – Clinical Node
      10 07         Cancer Staging – Clinical Metastasis
      10 08         Cancer Staging – Pathology Tumour
      10 09         Cancer Staging – Pathology Node
      10 10         Cancer Staging – Pathology Metastasis
      10 11         Cancer Staging – Summary Staging
      11 01         Intervention Date (20 occurrences)      M    M    M                        M         M          M
      11 02         Intervention Code (CCI)                 M    M    M                        M         M          M
      11 03         Status Attribute                        M    M    M                        M         M          M
      11 04         Location Attribute                      M    M    M                        M
      11 05         Extent Attribute                        M    M    M                        M
      11 06         Intervention Provider                   M         M                        M         M          M
      11 07         Intervention Provider Service           M         M                        M         M          M
      11 08         Intervention Tissue
      11 09         Intervention Time
      11 10         Intervention Location                   M         M
      11 11         Anesthetist                             M         M                                  M
      11 12         Anesthetist Technique                   M    M    M                        M         M          M




A–2                                                                                                          CIHI 2003
                                                                                           Data Quality Documentation:
                                                                               Discharge Abstract Database 2001–2002


Group & Field No.               Data Element                    NL   PE   NS     NB   QC   ON   MB   SK   AB   BC   NT   YK    NU
     11 13        OOH Indicator                                 M    M    M                          M         M         M
     11 14       OOH Institution Number                         M    M    M                          M         M         M
     11 15       Unplanned Return to OR                         M                                    M         M
     11 16       Died In OR                                     M    M    M                          M         M         M
     13 01       SCU Death Indicator (6 occurrences)            M    M    M                          M         M         M
     13 02       SCU Unit Number                                M    M    M                          M         M*        M
     13 03       SCU Admit Date                                 M    M    M                          M         M         M
     13 04       SCU Admit Time                                 M    M    M                          M         M         M
     13 05       SCU Discharge Date                             M    M    M                          M         M         M
     13 06       SCU Discharge Time                             M    M    M                          M         M         M
     13 09       Glasgow Coma Scale                             M    M    M                          M         M         M
    14 01-16     Basic Options – one digit boxes
     14 17       Basic Options – two digit box
     14 18       Basic Options – two digit box
     14 19       Basic Options – four digit box
    15 02-14     Mental Health                                  M
    16 01-13     Project Information (5 occurrences) 1 digit    M*        M*                                   M*
    16 14-15     Project Information – 2 digit box                        M*
    16 16-17     Project Information – 3 digit box                        M*                                   M*
     16 18       Project Information – Project Number 3 digit   M*        M*                                   M*
                 box
    17 01-07     Blood Information                              M    M    M                          M                   M
    18 01-09     Reproductive Care Information                  M    M    M                          M*        M*        M
    19 01-06     Licensed Vendor Assigned Values




CIHI 2003                                                                                                                A–3
Data Quality Documentation:
Discharge Abstract Database 2001–2002


                        Key Provincial Abstracting Differences, Fiscal 2001–2002
                       For Provinces Submitting in ICD-9/CCP or ICD9-CM Coding:
                                   NB, ON, MB, SK (part), AB, NT, NU
                                          Inpatient Discharges


  Legend
  M:                  Mandatory data element
  M*:                 Mandatory data element with a provincial variation
  *:                  Provincial variation
  Blank:              Optional data element
  NU:                 Not to be used
  Gray Shading:       Province does not submit in ICD-9/ICD-9-CM layout
  Black Shading:      Province does not submit to the DAD



  Group &
                    Data Element            NL   PE NS   NB QC ON MB SK       AB   BC NT YK NU
  Field No.
01 01       Province/Territory Number                    M     M    M    M    M       M     M

01 02        Institution Number                          M     M    M    M    M       M     M
01 03        Batch Year                                  M     M    M    M    M       M     M
01 04        Batch Period                                M     M    M    M    M       M     M
01 05        Batch Number                                M     M    M    M    M       M     M
01 06        Abstract Number                             M     M    M    M    M       M     M
01 08        Coder Number                                M     M    M    M    M       M     M
01 09        Chart Number                                M     M    M    M    M       M     M
01 10        Register Number                                   M*
01 11        Second Chart/Register Number                           M*        M*



03 01        Health Care Number                          M*    M*   NU   M*   M*      M*    M*
03 02        Postal Code                                 M     M    M    M    M       M     M
03 03        Residence Code                              M*    M*             M*      M*    M*
03 04        Gender                                      M     M    M    M    M       M     M
03 05        Prov/Terr Issuing HCN (new)                 M     M    NU   M    M       M     M

03 06        RFP (new)                                   M     M    NU   M    M
03 07        Marital Status (new)                        M     M*   NU   M*   M*      M*    M*
03 08        Birthdate                                   M     M    M    M    M       M     M
03 09        Estimated Birthdate                         M     M    NU   M    M       M     M
03 11-22     Prov/Terr Ancillary Data                    M*         M*   M*   M*

04 01        Admit Date                                  M     M    M    M    M       M     M
04 02        Admit Hour                                  M     M    M    M    M       M     M
04 04        Institution From                            M*    M*   M*   M*   M*      M*    M*
04 05        Admission Category                          M     M    M*   M    M       M     M
04 06        Entry Code                                  M     M    M*   M    M       M     M
04 07        Admit by Ambulance                          M     M              M       M     M



A–4                                                                                              CIHI 2003
                                                                                Data Quality Documentation:
                                                                    Discharge Abstract Database 2001–2002


  Group &
                   Data Element             NL   PE NS   NB QC ON MB SK       AB   BC NT YK NU
  Field No.
04 08       Readmission Code (change)                    M     M                      M     M

04 09       Unplanned Readmission Code                   M     M    NU
            (new)

04 10       Wait Time in Emergency (min.)                      M    NU
            (new)

05 01       Discharge Date                               M     M    M    M    M       M     M
05 02       Discharge Hour                               M     M    M    M    M       M     M
05 04       Institution To                               M*    M*   M*   M*   M*      M*    M*
05 05       Date Ready for Discharge

05 06       Reserve                                      M*
06 01       Exit Alive                                   M     M    M    M    M       M     M
06 02       Autopsy
06 03       Coroner/Medical Examiner                                *

06 04-11    Death Code                                   M     M  M M M               M     M
07 01       Main Patient Service                         M*    M* M* M* M*            M*    M*

07 02       Sub-service                                  M
07 03       Weight (0-29 days on                         M     M    M    M    M       M     M
            admission)
07 04       Abstract Overflow
08 01       Service Transfer                                        M*   M
08 01       Alternate Level of Care (ALC)                M     M    M    M    M       M     M

08 02       Sub-service                                                  M
08 03       Service Transfer Days                        M     M    M    M    M       M
09 01       Doctor Type                                  M     M    M    M    M       M     M
09 02       Doctor Number                                M     M    M    M    M       M     M
09 03       Doctor Service                               M     M    M    M    M       M     M
10 01       Diagnosis Prefix                             M     M    M    M    M       M     M
10 02       Diagnosis Code                               M     M    M    M    M       M     M
10 03       Diagnosis Suffix (ICD-9 only)                      M         M            M

10 04       Diagnosis Type                               M     M    M    M    M       M     M
11 01       Procedure Date                               M     M    M    M    M       M     M
11 02       Procedure Code                               M     M    M    M    M       M     M
11 03       Procedure Suffix                                        M*   M    M       M     M
11 04       Procedure Doctor Number                      M               M            M     M

11 05       Procedure Doctor Service                     M               M            M     M

11 06       Tissue Code                                  *     *    *    *    *       M*    M*
11 07       Procedure Time                               M



CIHI 2003                                                                                             A–5
Data Quality Documentation:
Discharge Abstract Database 2001–2002


  Group &
                     Data Element          NL   PE NS   NB QC ON MB SK     AB   BC NT YK NU
  Field No.
11 08       Intervention Location Code                  M*
            (change)
11 09        Anaesthetist                               M                          M     M
11 10        Anaesthetic Technique                      M              M           M     M

11 11        Out of Hospital Institution                      M*       M   M
             Number (new)

11 12        Unplanned Return to O.R.                   M
             (new)
12 01-06     Therapies                                        M
12 07        Discharge Planning                               M
12 08        Social Services                                  M
12 09        Preadmit Workup
13 01        SCU Death Indicator                        M          M   M   M       M     M
13 02        SCU Unit Number                            M*         M   M   M*      M     M
13 03        SCU Days                                   M              M   M       M     M
14 01-19     Basic Options                              *                          M*    *
15 02-14     *Mental Health                             M     M*
16 01-17     Project Information                                           M*
17 01-07     Blood Information (new)                    M     M        M   M       M     M

18 01-05     Therapeutic Abortion                       M     M        M   M       M     M
             Information (new)




A–6                                                                                           CIHI 2003
       Appendix B

   Data Element Changes
Implemented for 2001 DAD
  ICD-10-CA/CCI Abstract

     New Abstracted
      New Derived
        Modified
        Deleted
                                                                  Data Quality Documentation:
                                                      Discharge Abstract Database 2001–2002


New Abstracted Data Elements
Core: Mandatory data element with no provincial variation
Non-core: Mandatory data elements with provincial variation OR optional data element

 New Abstracted
                          Status                           Description
 Data Elements
 Maternal/               Core       Mother’s chart/register number is recorded on baby’s
 Newborn Chart/                     chart and baby A’s chart/register number is recorded
 Register Number                    on the mother’s chart.

 Gestational Age         Non-core   Measured in completed weeks at delivery. Collected
                                    for both abortion and obstetrics patients. The data
                                    element is new only for obstetrics patients

 Delivery Time           Non-core   Time of delivery (date of delivery is already recorded
                                    in the intervention field)

 Obstetrical History:    Non-core   These new data elements are to be collected on the
                                    mother’s chart for all deliveries and abortions. This
 -   # previous term                information is new for obstetrics patients. The
     pregnancies                    information was previously collected for therapeutic
 -   # previous pre-                abortion patients, but using slightly different
     term deliveries                definitions
 -   # previous
     pregnancies
     ending in
     spontaneous
     abortion
 -   # previous
     pregnancies
     ending in
     therapeutic
     abortion
 -   # previous live
     births (OBS only)

 Breastfeeding at        Non-core   Indicates whether a mother was breastfeeding her
 Discharge                          infant at the time of discharge from hospital.

 SCU admit date/time     Core       Collects the data required to derive SCU length of
                                    stay in hours.
 SCU discharge
 date/time
 Discharge Disposition   Core       A single field to track the exit status of the patient.




CIHI 2003                                                                                     B–1
Data Quality Documentation:
Discharge Abstract Database 2001–2002


 New Abstracted
                        Status     Description
 Data Elements
 Glasgow Coma Scale     Core       Recorded on admission for those over three years of
 (GCS)                             age that have head injuries as a most responsible
                                   diagnosis.
                                   There is a paediatric GCS, which uses the same 15-
                                   point scale. This may be completed at the option of
                                   the hospital
 Cancer Staging         Non-core   Cancer staging is done at the time of initial diagnosis
                                   for oncology patients. It assesses the degree to which
                                   the cancer has spread. CIHI has adopted an
                                   international classification system called TNM
                                   (Tumour Node Metastases)



New Derived Data Elements
 New Derived
                                                  Description
 Data Elements
 Wait Time in ER     This derived data element reflects the difference between the
                     date/time of decision to admit and the date/time the patient left ER,
                     measured in hours.

 CIHI assigned       This data element will be a patient (as opposed to provider) based
 patient group       categorization. It will be in addition to the existing MCC and patient
                     service elements.

 SCU LOS             This derived data element reflects the difference between the
                     date/time a patient is admitted to SCU and the date/time the patient
                     is discharged from SCU, measured in hours.

 Vendor              This set of data elements compares value-added data elements
 MCC/CMG/Plx/RI      assigned by the hospital’s abstracting vendor to those assigned by
 W/DPG               CIHI.
 Readmission         Tracks unplanned readmissions for select interventions and
 indicator           diagnoses for hospitals within a province.




B–2                                                                               CIHI 2003
                                                                   Data Quality Documentation:
                                                       Discharge Abstract Database 2001–2002


Modified Data Elements
The following are data elements that have been substantially revised for the new abstract.

 Modified Data Elements        Status                        Description
 Health care number           Core       Left justify in all provinces/territories for
                                         consistency.
 Province/territory issuing   Core       Consistent national mini-coding to facilitate
 health care number                      comparisons.
 Responsibility for           Core *     Consistent national mini-coding to facilitate
 payment (RFP)                           comparisons.
 Postal code                  Core       XX will be the standardized code to track high-
                                         need homeless population.
 Gender                       Core       New mini-coding to be consistent with HL7
                                         information standards
 Admit category               Core       Expanded mini-coding to address evolving data
                                         needs (includes cadavers admitted for organ
                                         retrieval).

                                         Consistency of definitions (for newborns and
                                         stillborns) with MIS.
 Modified Data Elements       Status     Description
 (cont’d)
 Entry code                   Core       Expanded mini-coding to address evolving data
                                         needs (includes admissions from the reporting
                                         hospital’s clinics and day surgery).

                                         Consistency of definitions for (newborns and
                                         stillborns) with MIS.
 Readmit code                 Non-core   Simplify mini-coding to improve data quality.

 Weight                       Core       Use consistent definition of <29 days in all
                                         provinces/territories.
 Provider number              Core       Expansion of field size.
 Provider service             Core       Update mini-coding to match Royal College of
                                         Physicians and Surgeons.
 Diagnosis                    Core       Changed to accommodate ICD-10-CA/CCI.
 Intervention                 Core
 Intervention provider        Non-core   Expansion of field size.
 number
 Intervention provider        Non-core   Update mini-coding to match Royal College of
 service                                 Physicians and Surgeons.
 Intervention time            Non-core   Standardize time to patient in/patient out. This
                                         should improve comparability of data.


CIHI 2003                                                                                   B–3
Data Quality Documentation:
Discharge Abstract Database 2001–2002


    Modified Data Elements    Status                         Description
    Intervention location    Non-core    Standardize mini-coding (Ontario will use a
                                         different mini-coding system).
    Anesthetist number       Non-core    Expansion of field size.
    Anesthetic technique     Core *      Update mini-coding list to capture more recently
                                         developed techniques.
    SCU unit number          Core *      Develop standardized mini-coding to facilitate
                                         comparisons with MIS codes.
* = shift from non-core to core status



Deleted Data Elements
Coding resources must be focused on capturing only those data elements agreed to be
most important. As a result, the following data elements have been confirmed for deletion.
This information is either no longer required, is redundant or is not of national interest. If
an individual facility or province/territory needs to capture any of these elements on an
ongoing basis, other areas of the DAD abstract such as provincial/territorial ancillary data,
project field or basic options can be used.
•     Marital status
•     Reserve field
•     Date ready for discharge
•     Exit alive
•     Autopsy
•     Coroner/medical examiner
•     Death codes (except SCU and OR death)
•     Diagnosis suffix
•     Therapies
•     Pre-admit work up




B–4                                                                                 CIHI 2003

				
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