Trends in COPD bronchitis by mikeholy

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									                                                                                                                                                                                       Factsheet 2003/1


                                                                                                            Trends in COPD

    Public Health Sciences Dept., St George’s Hospital Medical School, Cranmer Terrace, London SW17 0RE                             laia@sghms.ac.uk                 http://www.sghms.ac.uk/depts/laia/laia.htm



 Chronic obstructive pulmonary disease (COPD) is a                                    Table 1: ICD codes for chronic lower respiratory obstructive
 relatively new name for an old condition. As a                                       diseases
                                                                                                  ICD 9                          ICD 10
 diagnostic category in hospital admissions and mortality
 data, the label "chronic airways obstruction" was first                            490-496                Chronic obstructive pulmonary                                    J40-J47         Chronic lower respiratory
                                                                                                           disease and allied conditions                                                    diseases
 established in 1979 with the introduction of ICD 9,                                490                    Bronchitis not specified as                                      J40             Bronchitis not specified as
 largely replacing chronic bronchitis and emphysema. In                                                    acute or chronic                                                                 acute or chronic
 ICD 10, introduced for coding admissions from April                                491                    Chronic bronchitis                                                 J41,J42       Chronic bronchitis
 1996 and from 2001 for mortality, the term used is                                 492                    Emphysema                                                        J43             Emphysema
                                                                                    496                    Chronic airways obstruction                                      J44             Chronic airways obstruction
 "Other chronic obstructive pulmonary disease" (Table
 1). The WHO predicts that COPD will rise up the
 rankings of chronic disease prevalence from 12th to 5th                              Figure 1: Seasonal variations in GP consultations and
 place by 2020 world wide, but the trends in the UK tend                              prescribing for COPD, England 1991-95
 not to follow that global pattern.                                                        5                                                                                                                                140
                                                                                                                                                  Consultations                   Prescriptions

                                                                                                                                                                                                                            120
                                                                                           4

 Prevalence                                                                                                                                                                                                                 100

                                                                                           3
                                                                                                                                                                                                                            80
 There are few data on the prevalence of COPD in the
                                                                                                                                                                                                                            60
 UK. The Health Survey for England 1996 reported on                                        2

 relative lung function and chronic respiratory symptoms                                                                                                                                                                    40
                                                                                           1
 in the adult population. The prevalence of low FEV1                                                                                                                                                                        20

 values was 11% in men and 8% in women (see footnote)                                      0                                                                                                                                0
                                                                                                   1       3     5     7     9 11 1 3 1 5 17 19 2 1 2 3 25 27 2 9 3 1 33 35 37 3 9 4 1 43 45 4 7 4 9 51
 while the prevalence of chronic cough or phlegm
                                                                                                                                                         Week of year
 production was 19% in men and 14% in women. The
                                                                                                                                                                                                           Source: GPRD
 General Household Survey records self-reported
 diagnoses of chronic bronchitis and emphysema. These
 showed a far lower prevalence of 0.9% in men and 0.7%                                Figure 2: Admissions for chronic obstructive pulmonary
                                                                                      diseases including chronic bronchitis and emphysema, all
 in women in 2001 which indicates that much early                                     ages, England 1991-2001
 disease is unrecognised.
                                                                                                                                                                                                                COPD (including
                                                                                               2000
                                                                                                                                                                                                                chronic bronchitis
                                                                                               1800                                                                                                             and emphysema)
                                                                                                                                       code change                                                              COAD not
 GP consultations                                                                              1600
                                                                                                                                                                                                                elsewhere
                                                                                               1400                                                                                                             classified (ICD 9)
                                                                                                                                                                                                                Other COPD (ICD10)
 Factsheet 96/3 reported patient-consulting rates from the                                     1200

                                                                                               1000
 three national Morbidity Surveys in General Practice                                           800
                                                                                                                                                                                                                Chronic bronchitis


 which showed no increase between 1971 and 1991 for                                             600
                                                                                                                                                                                                                Emphysema
                                                                                                400
 patients diagnosed with chronic bronchitis. Analysis of                                        200
 the General Practice Research Database (GPRD)                                                         0
                                                                                                               91/92       92/93   93/94   94/95     95/96   96/97    97/98    98/99    99/00    00/01
 showed a prevalence of GP consultations for COPD of
                                                                                                                                                   Financial year
 1.6% in men and 1.4% in women in 1997. There was a
                                                                                                                                                                                                           Source: HES
 small upward trend in women from 1990-97 and a
 levelling off in men during that period. However, these
 figures will not include those who have COPD but                                     Figure 3: Admission rates for COPD (including chronic
 without symptoms of sufficient severity to report that                               bronchitis and emphysema) by age, England 1991-2000
 year. The GPRD also shows the predicted winter                                                                                       0-44             45-64             65-74             75-84          85+
 seasonality of consultations for COPD (figure 1). In                                  12000
 contrast, prescribing for COPD-like symptoms is                                       10000
 constant throughout the year except during the                                           8000
 Christmas/New Year period.
                                                                                          6000

                                                                                          4000

                                                                                          2000
 Hospital admissions
                                                                                               0
 Most admissions for chronic obstructive pulmonary                                                         1991              1992          1993        1994          1995        1996           1997     1998       1999          2000


 diseases are coded as COPD or COAD, rather than                                                                                                                     Year

 chronic bronchitis or emphysema (figure 2). Admission                                                                                                                                                     Source: HES



Supported by: • British Lung Foundation • National Asthma Campaign • British Thoracic Society
                    020 7831 5831              020 7226 2260              020 7831 8778
rates for all COPD diagnoses combined have increased                      Figure 4: Trends in admission rates for COPD (including
across all age groups over the last decade (figure 3) and                 chronic bronchitis and emphysema) in males and females, all
this is due largely to factors other than a diagnostic shift              ages, England 1991-2000
from asthma to COPD. The increase is slightly greater
in females than in males but the trends are broadly                          2500
similar (figure 4). COPD admissions as a percentage of                                                                  Males              Females


all admissions have also increased steadily from 0.5% in                     2000


1991 to 1% in 2000.                                                          1500


                                                                             1000

Mortality
                                                                              500

Age-adjusted mortality rates for COPD have fallen over
                                                                                  0
the last twenty years in males from 1070 to 634 per                                      1991   1992   1993      1994      1995        1996      1997      1998     1999       2000
million (largely in those over the age of sixty five)                                                                             Year
(figure 5). In contrast rates have increased in females
overall from 230 to 323 per million over the same                                                                                                                        Source: HES

period. This increase in females has been in the 65-84
years age group while the rates at younger ages have
fallen slightly (figure 6). It is notable that there is a
greater divergence in trends in COPD mortality between
the sexes than in admissions or GP consultations. This
                                                                          Figure 5: Trends in age-adjusted mortality rates from COPD
might be due to a sex difference in the pathology of the
                                                                          in males and females, England & Wales 1980-2000
airway inflammatory process, differences in perception
of symptom severity or in the natural history in the
terminal stages of the disease.
                                                                             1400                                         Males                         Females
The geographical pattern for mortality tends to                              1200
concentrate over industrialised areas, but is broadly                        1000
similar between males and females (LAIA factsheet                             800
96/1).
                                                                              600

                                                                              400


   Summary                                                                    200


   • The prevalence of diagnosed COPD is                                          0
                                                                                      1980                1985                           1990                     1995                2000

       about 1.5% in the UK and prevalence of                                                                                     Year

       reduced lung function is about 10%.
                                                                                                                                                                         Source: HES
   •   COPD continues to be responsible for over
       90,000 hospital admissions a year which,
       with an average duration of stay of 11 days,
       means nearly a million hospital bed days
       per year.
                                                                          Figure 6: Trends in deaths in females from COPD by age,
   •   Mortality continues to rise in women but                           England & Wales 1980-2000
       has fallen in men.
                                                                                                       0-44             45-64            65-74          75-84            85+

   •   The disparity between the trends for                                4000

                                                                           3500
       mortality, hospital admissions and GP                               3000
       consultations between the sexes remains                             2500

       unexplained.                                                        2000

                                                                           1500

Footnote                                                                   1000

                                                                            500
Forced Expiratory Volume in the first second (FEV 1).
                                                                              0
This is the volume that can be expelled in the first second of forced
                                                                                  1980                  1985                        1990                          1995                 2000
expiration, starting from a full inspiration. A low FEV1 is a marker of
                                                                                                                                Year
airway narrowing, indicative of COPD, asthma or other obstructive
lung diseases. 'Low' in this case meant that people were less than 1.64
standard deviations lower than the predicted level based on a reference                                                                                                  Source: ONS
population (that is, within the lowest expected 5% of the predicted
population).


Sources
Health Survey for England 1996 (http://www.archive.official-documents.co.uk/document/doh/survey96/ehtitle.htm)
General Household Survey 2000
Soriano JB et al. Recent trends in physician diagnosed COPD in women and men in the UK. Thorax 2000; 55: 789-794
ONS Mortality Statistics

								
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