Evidence-Based Public Health: A Course in Chronic Disease
Prevention MODULE 1: Introduction & Overview Ross Brownson
March 2013
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WELCOME!! 2
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... If we did not respect the evidence, we would have very
little leverage in our quest for the truth. Carl Sagan 3
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Public health workers deserve to get somewhere by design, not
just by perseverance. McKinlay and Marceau 4
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Acknowledgements Thanks to Garland Land & Missouri
Department of Health and Senior Services Terry Leet, Saint Louis
University Funding and technical support from the MDHSS, Chronic
Disease Directors and the Centers for Disease Control and
Prevention, and the World Health Organization, CINDI Austria, CINDI
Lithuania 5
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Introductions Course Director Ross Brownson Course Coordinator
Wes Gibbert 6
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Instructors Ross Brownson Anjali Deshpande Darcy Scharff Kathy
Gillespie 7
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Ground Rules Attendance leave cell phones, beepers on stun
Active participation is sought all questions are welcome No tests
8
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Ground Rules (cont) Formative feedback to instructors After
sessions, commit to trying it out/using readings you and/or staff
in many cases, we hope this amounts to train-the- trainer 9
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Our training framework 10
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Retool Discontinue Disseminate widely
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Course Objectives
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MODULE 1: Introduction And Overview 1.Understand the basic
concepts of evidence-based decision making. 2.Introduce some
sources and types of evidence. 3.Describe several applications
within public health practice that are based on strong evidence and
several that are based on weak evidence. 4.Define some barriers to
evidence-based decision making in public health settings. 13
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Others with each module
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What is Evidence? 15
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What is Evidence? Scientific literature in systematic reviews
Scientific literature in one or more journal articles Public health
surveillance data Program evaluations Qualitative data Community
members Other stakeholders Media/marketing data Word of mouth
Personal experience 16 Objective Subjective Like beauty, its in the
eye of the beholder
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What are the evidence domains? 17
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Best available research evidence Environment and organizational
context Population characteristics, needs, values, and preferences
Resources, including practitioner expertise 18 Decision-making
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Are we talking only of scientific evidence? 19
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Where am I? Youre 30 yards above the ground in a balloon You
must be a researcher Yes. How did you know? Because what you told
me is absolutely correct but completely useless You must be a
policy maker Yes, how did you know? The problem 20
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How are decisions generally made in public health settings?
Resources/funding availability (C-E) Peer reviewed
literature/systematic reviews Media driven Pressure from policy
makers or administrators 21
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How are decisions made? (cont) Expert opinions (e.g.,
academics, community members) History/inertia Anecdote OR Combined
methods, based in sound science How to make the best use of
multiple sources of information & limited resources?? 22
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EB Decision-Making Understanding a process Finding evidence for
decisions Creating new evidence for decisions 23
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Some Key Characteristics of EBPH 1.Making decisions based on
the best available peer-reviewed evidence (both quantitative and
qualitative research); 2.Using data and information systems
systematically; 3.Applying program planning frameworks (that often
have a foundation in behavioral science theory); 24
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Some Key Characteristics of EBPH 4.Engaging the community in
assessment and decision making; 5.Conducting sound evaluation; and
6.Disseminating what is learned to key stakeholders and decision
makers. 25
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Why do Programs/Policies Fail? Choosing ineffective
intervention approach Selecting a potentially effective approach,
but weak or incomplete implementation or reach Conducting and
inadequate evaluation that limits generalizability Paying
inadequate attention to adapting an intervention to the population
and context of interest
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Examples Based on Varying Degrees of Evidence? 27
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Examples Based on Varying Degrees of Evidence? California
Proposition 99 smoking as key public health issue effects of price
increases 0.25 per pack increase in 1988 earmarked for tobacco
control with strong media component for 1988-93, doubling of rate
of decline against background rate 28
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Prevalence (%) = 22.1 California adult smoking prevalence by
region, 1990 29
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California adult smoking prevalence by region, 1996 Prevalence
(%) = 22.1 30
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California adult smoking prevalence by region, 1999 Prevalence
(%) = 22.1 31
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California adult smoking prevalence by region, 2002 Prevalence
(%) = 22.1 32
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What Worked? Comprehensive program and tax increases in CA and
MA resulted in: 2 - 3 times faster decline in adult smoking
prevalence Slowed rate of youth smoking prevalence compared to the
rest of the nation Accelerated passage of local ordinances Similar,
though later, experience in OR & AZ, and in population segments
of FL
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Examples Based on Varying Degrees of Evidence? Missouri TASP
Program MO child restraint law in 1984 After 8 years, compliance at
50% TASP Program in 1992 Report license plates of children not
properly restrained In 1995, phone survey and observations showed
low effectiveness 34
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Growth of Evidence-Based Medicine the integration of best
research evidence with clinical expertise and patient values. First
introduced in 1992 Key reasons for EBM Overwhelming size and
expansion of the medical literature Inadequacy of textbooks and
review articles Difficulty in synthesizing clinical information
with evidence from scientific studies 35
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What is EBM? Process has grown recently pathophysiology
cost-effectiveness patient preferences In large part, learning to
read & assimilate information in journals 36
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What is EBM? Sackett & Rosenberg: 1.convert information
needs into answerable questions; 2.track down, with maximum
efficiency, the best evidence with which to answer them (from the
clinical examination, the diagnostic laboratory, the published
literature, or other sources; 37
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What is EBM? (cont) Sackett & Rosenberg: 3.critically
appraise that evidence performance for its validity (closeness to
the truth) and usefulness (clinical applicability); 4.apply the
results of this appraisal in clinical practice; and 5.evaluate
performance 38
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Differences Between EBPH and EMB? 39
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groupindividualDecision making less formal no certification
required more formal certification required Training longer
intervalshorter interval Time from intervention to outcome
quasi-experimental studies experimental studies Quality &
volume of evidence EBPHEBM Characteristics Differences Between EBM
& EBPH 40
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Types of Evidence 41 CharacteristicType OneType TwoType Three
Typical Data/ Relationship Size and strength of preventable
riskdisease relationship (measures of burden, etiologic research)
Relative effectiveness of public health intervention Information on
the adaptation and translation of an effective intervention Common
setting Clinic or controlled community setting Socially intact
groups or community-wide Example Smoking causes lung cancer Price
increases with a targeted media campaign reduce smoking rates
Understanding the political challenges of price increases
QuantityMoreLess ActionSomething should be done.This particular
intervention should be implemented How an intervention should be
implemented
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In our research paradigms we may rely too heavily on randomized
designs for community-based studies
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The best is the enemy of the good -Voltaire The problem of
randomized trials and parachutes.
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The effectiveness of parachutes has not been subjected to
rigorous evaluation by using randomised controlled trials. We think
that everyone might benefit if the most radical protagonists of
evidence based medicine organised and participated in a double
blind, randomised, placebo controlled, crossover trial of the
parachute. Smith and Pell, BMJ, 2004 44
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What are Some Useful Tools? Systematic reviews e.g., Guidelines
meta-analysis Economic evaluation Risk assessment Public health
surveillance 45
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Systematic Reviews One of the best Guide to Community
Preventive Services sponsored by the CDC follows work from the US
Preventive Services Task Force 15 member task force mainly HP 2010
areas of emphasis www.thecommunityguide.org 46
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Training Resources 48
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49 On Line Resource Both individual level and community level
issues Sample modules: www.ebbp.org
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Challenges & Barriers 50
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Getting a new idea adopted, even when it has obvious
advantages, is often very difficult. -- Everett Rogers, Diffusion
of Innovations 51
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Barriers to EBPH Lack of leadership in setting a clear and
focused agenda for evidence-based approaches Lack of a view of the
long-term horizon for program implementation and evaluation
External (including political) pressures drive the process away
from an evidence-based approach
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Barriers to EBPH (cont) Inadequate training in key public
health disciplines Lack of time to gather information, analyze
data, and review the literature for evidence Lack of
incentives
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When evidence is not enough Cultural and geographical
limitations Formal approaches, largely western world phenomena
Evidence is often a luxury in many parts of the world Bias in
deciding what gets studied Emerging health issues Disaster
preparedness Community-based & participatory approaches May
seem counter-intuitive to a strict evidence- based process 54
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In your work Diverse set of issues/evidence base Tobacco Cancer
prevention & control Environmental health Genomics Obesity
prevention Poverty, social inequities War Variability in staffing
and training needs Turnover in agencies Funds/infrastructure are
limited in every program, country 55
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Summary (continued) Numerous challenges and barriers course
will highlight some course is only a beginning; remember to try
things out on regular basis Remember sound public health practice
is a blend of art and science 56