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									Evidence-based Public Health . . .
and some reasons why we need it

    Russell S. Kirby, PhD, MS, FACE
        Professor and Vice Chair
 Department of Maternal and Child Health
         School of Public Health
  University of Alabama at Birmingham
 Describe the evidence-based practice (EBP)
 Identify key characteristics of evidence-
  based public health (EBPH)
 Differentiate between EBP and EBPH
 Review several recent controversies and
  their impact
 Speculate on the future uses of evidence
 Brief Summary for Those Who Are Knitting, Doing
  Crossword Puzzles, or Discerning the Geometric
            Pattern in the Carpeting
 Evidence-based public health is the leading edge of
  modern public health practice.
 It requires the same level of diligence with
  understanding principles of study design, sources of
  bias, internal and external generalizability, and research
  synthesis as is necessary in evidence-based practice.
 Many of the necessary materials are ephemeral, but this
  is also true of clinical research due to the publication
 Several examples serve to show how this can work well,
  and . . . perhaps, not so well.
The Practice of Evidence-based Practice
 “integrating individual clinical expertise with
  the best available external clinical evidence
  from systematic research”
 individual clinical expertise: the proficiency
  and judgment acquired through experience
  and practice in clinical settings
 external clinical evidence: clinically relevant
  research, from basic medical science and
  patient-centered clinical research
          How Do We Practice EBP?
 EBP is a life-long process of self-directed learning, in
  which caring for patients creates for the clinician a need
  for clinically important information about diagnosis,
  therapy, prognosis, and other clinical and health
  services issues. In this process, we:
   – Convert information needs into answerable questions
     (testable hypotheses)
   – Track down the best evidence with which to answer
   – Critically appraise the evidence for validity and
   – Apply the results of this appraisal in clinical practice
   – Evaluate performance
                   Why EBP?
 New types of evidence are being generated which,
  when known and understood, have the potential to
  create frequent and major changes in the way we care
  for our patients
 Although we need this evidence daily, we usually fail
  to get it
 Because of this, both our up-to-date knowledge and
  clinical performance deteriorate over time
 Trying to remedy this personally through traditional
  CME/CEU programs generally doesn‟t improve clinical
 A different approach to clinical learning has been
  shown to keep its practitioners up-to-date. EBP is that
  different approach.
              Quality of Evidence
I:    Evidence obtained from at least one properly
    randomized controlled trial.
II-1: Evidence obtained from well-designed controlled trials
    without randomization.
II-2: Evidence obtained from well-designed cohort or case-
    control analytic studies, preferably from more than one
    center or research group.
II-3: Evidence obtained from multiple time series with or
    without the intervention. Dramatic results in uncontrolled
    experiments (i.e. results of introduction of penicillin
    treatment in 1940s) could also be regarded as this type of
III: Opinions of well-respected authorities, based on clinical
    experience; descriptive studies and case reports; or
    reports of expert committees.
What is Evidence-based
   Public Health?
 Develop            Sequential Framework for Enhancing
 an initial
                       Evidence-based Public Health
of the issue                  (Brownson, et al.)
                    Tools: rates and risks,
                    surveillance data
    Quantify                                     Evaluate
    the issue       Tools: systematic reviews, the program
                    risk assessment, economic    or policy
        Search the                                     Implement
   scientific literature         Re-tool
      and organize                             Develop an
       information                                action
                       Develop and               plan and
                    prioritize program          implement
         Refine the       options
         issue                                interventions
Key Differences Between EBP and EBPH
Characteristic                  EBP                    EBPH
Quality of evidence     Experimental Studies       Observational and quasi-
                                                    experimental studies

Volume of evidence              Larger                  Smaller

Time from intervention          Shorter                 Longer
  to outcome

Professional training     More formal, with           Less formal,
                        certification/licensing   no standard certification

Decision making                 Individual                Team
 Comparison of the Types of Scientific Evidence

Characteristic           Type I                  Type II
Typical data/     Strength of preventable Relative effectiveness of
relationship    risk-disease relationship public health intervention

Common setting     Clinic or controlled   Socially intact groups or
                     community setting        community-wide

Quantity of evidence        More                       Less

Action      “Something should be done”     “This should be done”
         Types of evidence
 Type I: „something should be done‟
  – Analytic data on specific health
    condition and its link to preventable risk
 Type II: „specifically, this should be
  – Focus on relative effectiveness of
    specific interventions to address a
    particular health condition
The Realistic Evidence-Based Rating Scale
 Class 0: Things I believe
 Class 0a:Things I believe despite the available data
 Class 1: Randomized controlled clinical trials that
  agree with what I believe
 Class 2: Other prospectively collected data
 Class 3: Expert opinion
 Class 4: Randomized controlled clinical trials that
  don‟t agree with what I believe
 Class 5: What you believe that I don‟t
          Some examples
 VBAC and Cesarean section
 Folic Acid and prevention of neural
  tube defects
 Back to Sleep
 HRTs: the mystery continues
Trends in Cesarean Deliveries and VBACs, United States 1990-2002


 Percent of Live Births


                                                                              Total C- Section
                          10.0                                                Rate
                                                                              Primary C-Section
                                                                              VBAC Rate

                                 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
 The velocity of the increase in the primary
  Cesarean section rate and the decline in
  VBAC rates in the recent past in the US is
 In less than five years, more than ten years
  of increasing VBAC rates has disappeared.
 Is this a good thing, or even a matter of
Trends in Induction of Labor, United States, 1980-2002

                                                           Induction NHDS
                                                          Medical Induction NHDS
    Percent of Live Births/Deliveries

                                                          Surgical Induction NHDS
                                                          Induction-Birth Certificates




                                               1980 1985 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

 Rates of induction have increased
  dramatically across the nation.
 There are differences based on data
  source, but no one can dispute the
  direction of the trend.
 Let‟s look at some specifics for
Trends in Induction, C-Section, and VBAC, Alabama 1998-2002




                                                  C-Section Rate
                                                  VBAC Rate

                                                  Primary C-S Rate
          15                                      Repeat C-S Rate
                                                  Induction %


               1998   1999   2000   2001   2002
    Is this a public health concern?
 Con: public health does not focus on clinical
  management of patients. That is in the
  responsibility of the health care system, peer
  review, quality compliance, and provider
 Pro: Cesarean section is among the most
  common surgical procedures. It is more
  expensive per total hospital stay than vaginal
  delivery, and leads to more complications
  and re-hospitalizations.
    Is this a public health concern?
 The Public Health Service has established
  goals for the year 2010 promoting continued
  reduction in overall Cesarean section rates
  and increases in VBAC rates for the United
  – Objective 16-9a: Reduce C-S among low-risk
    nulliparous women
  – Objective 16-9b: Reduce C-S among women with
    prior Cesarean birth
Where do Alabama and Wisconsin fit in?
 Historically, Wisconsin has had one of the
  lowest C-section rates in the US. Alabama, on
  the other hand, generally has one of the highest.
 In 1960, the national rate was 4%, and from the
  1970s on the C-section rate has tended to be 25-
  33% lower than the national rate.
 Wisconsin has also been a leader in the use of
  vaginal birth after Cesarean section, while
  Alabama has been comparatively slow to adopt.
   Total Cesarean Section Rate and VBAC Rate
              by Race of Mother, 2001
United States Compared to Wisconsin and Alabama

                        US     Wisconsin       Alabama
                       Rate   Rate State Rank Rate State Rank
Total C-Section Rate 24.4      19.1 45th highest 27.6      4th highest
  White Non-Hispanic   24.5    19.7                 28.5
  Black Non-Hispanic   25.9    16.9                 26.8
  Hispanic             23.6    18.4                 21.5

 VBAC Rate             16.4    23.0   43rd lowest   11.8   6th lowest
  White Non-Hispanic   16.8    22.3                 11.0
  Black Non-Hispanic   16.7    28.8                 13.5
  Hispanic             14.7    22.9                 12.3
       Risk Factors Associated with
            Cesarean Delivery
 Many patient, health care system, and physician
  characteristics are associated with higher or lower
  rates of Cesarean section.
 A partial list includes maternal age (increased risk),
  parity (decreased risk), obesity and short stature
  (increased risk), estimated fetal weight > 4000g
  (increased risk), breech presentation (increased
  risk), delivery in teaching hospital (decreased risk),
  private insurance (increased risk), fear of
  malpractice suits (greatly increased risk).
Method of Delivery by Body Mass Index (BMI)
 Sinai Samaritan CNM Patients, 1994-1998
  BMI         Cesarean Vaginal         Total
              No. %    No. %           No. %

  < 20        9    3.2   271   97.1    279    15
  20 - 24.9   31   3.9   759   96.1    790    42
  25 - 25.9   28   6.5   407   93.8    434    23
  30 +        28   7.4   348   92.6    376    20

  Total     96 5.1 1785 94.9           1881
  Chi-Square (3 df) = 10.19, p<0.018
        Adjusted Odds of Cesarean Delivery,
          SSMC CNM Patients, 1994-1998
Characteristic           Odds Ratio    95 % C.I.          p-value
Obesity (BMI 30 +)          3.26     (1.60, 6.67)         0.0012
Weight Gain > Recommended 2.09        (1.06, 4.11)        0.0326
Short Stature (< 155 cm)    2.52      (1.12, 5.64)        0.0252
No Previous Live Births     4.30    (1.78, 10.37)         0.0012
Age 35 +                    4.93    (1.08, 22.61)         0.0399
 Failure to Progress       60.42    (29.86, 122.24)       0.0001
Breech Presentation        458.34   (133.74, 999)         0.0001
Placental Abruption        82.56    (19.00, 358.67)        0.0001
                            5.71      (2.58, 12.64)       0.0001
Fetal Distress
                            8.68      (1.09, 69.20)       0.0412
Severe Pre-eclampsia
       Adjusted for race of mother (black), marital status,
       primigravidity and very low birth weight.
    Clinical Documentation of
    Previous Cesarean Section
 Most clinicians practice in settings that
  do not have comprehensive, unified
  clinical informatics applications.
 In a patient who‟s previous delivery was
  with another provider, how likely is it
  that the patient‟s history will document
  the type of incision, the position of the
  uterine scar, whether single- or double-
  suturing was used, etc?

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