Evidencebased Public Health . . . and some reasons why we need it

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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

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Objectives

• Describe the evidence-based practice (EBP)
  paradigm
• 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

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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 bias.
• Several examples serve to show how this can work
  well, and . . . perhaps, not so well.

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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

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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
  them
• Critically appraise the evidence for validity and
  usefulness
• Apply the results of this appraisal in clinical
  practice
• Evaluate performance

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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 doesnt
  improve clinical performance
• A different approach to clinical learning has
  been shown to keep its practitioners up-to-date.
  EBP is that different approach.

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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 evidence.
• III Opinions of well-respected authorities,
  based on clinical experience descriptive studies
  and case reports or reports of expert
  committees.

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What is Evidence-based Public Health?
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Develop an initial statement of the issue
Sequential Framework for Enhancing
Evidence-based Public Health (Brownson, et al.)
Tools rates and risks, surveillance data
Quantify the issue
Evaluate the program or policy
Tools systematic reviews, risk assessment,
economic data
Implement
Search the scientific literature and organize
information
Re-tool
Develop an action plan and implement interventio
ns
Develop and prioritize program options
Refine the issue
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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

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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

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Types of evidence

• Type I something should be done
• Analytic data on specific health condition and
  its link to preventable risk factor(s)
• Type II specifically, this should be done
• Focus on relative effectiveness of specific
  interventions to address a particular health
  condition

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The Realistic Evidence-Based Rating Scale

• Class 0 Things I believe
• Class 0aThings 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 dont agree with what I believe
• Class 5 What you believe that I dont

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Some examples

• VBAC and Cesarean section
• Folic Acid and prevention of neural tube defects
• Back to Sleep
• HRTs the mystery continues

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Trends in Cesarean Deliveries and VBACs, United
States 1990-2002
30.0
25.0
20.0
Percent of Live Births
15.0
Total C- Section
Rate
10.0
Primary C-Section
Rate
5.0
VBAC Rate
0.0
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
Year
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Trends

• 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
  unprecedented.
• 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 concern?

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Trends in Induction of Labor, United States,
1980-2002
25.0
Induction NHDS
Medical Induction NHDS
20.0
Surgical Induction NHDS
Induction-Birth Certificates
15.0
Percent of Live Births/Deliveries
10.0
5.0
0.0
1980
1985
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
Year
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Trends

• 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.
• Lets look at some specifics for Alabama

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Trends in Induction, C-Section, and VBAC, Alabama
1998-2002
35
30
25
C-Section Rate
20
VBAC Rate
Primary C-S Rate
Percent
15
Repeat C-S Rate
Induction
10
5
0
1998
1999
2000
2001
2002
Year
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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
  organizations.
• 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.

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Is this a public health concern?(continued)

• 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 States.
• Objective 16-9a Reduce C-S among low-risk
  nulliparous women
• Objective 16-9b Reduce C-S among women with
  prior Cesarean birth

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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.

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Total Cesarean Section Rate and VBAC Rateby Race
of Mother, 2001United States Compared to
Wisconsin and Alabama
Wisconsin
US
Alabama
Rate
Rate
State Rank
Rate
State Rank
Total C-Section Rate
19.1
45th highest
27.6
4th highest
24.4
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
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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).

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Method of Delivery by Body Mass Index
(BMI)Sinai Samaritan CNM Patients, 1994-1998

• BMI Cesarean Vaginal Total
• No. No. No.
• 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

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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 (
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
60.42
(29.86, 122.24)
0.0001
Failure to Progress
458.34
(133.74, 999)
0.0001
Breech Presentation
82.56
(19.00, 358.67)
0.0001
Placental Abruption
0.0001
5.71
(2.58, 12.64)
Fetal Distress
0.0412
8.68
(1.09, 69.20)
Severe Pre-eclampsia
Adjusted for race of mother (black), marital
status, primigravidity and very low birth weight.
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Clinical Documentation of Previous Cesarean
Section

• Most clinicians practice in settings that do not
  have comprehensive, unified clinical informatics
  applications.
• In a patient whos previous delivery was with
  another provider, how likely is it that the
  patients history will document the type of
  incision, the position of the uterine scar,
  whether single- or double-suturing was used, etc?