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Objectives and Competencies
Learn the definition of EBPH
Introduction to the process of EBPH
Describe steps associated with EBPH in public
health.
Identifies relevant and appropriate data and
information sources.
“ …If we did not respect the evidence, we would
have very little leverage in our quest for the
truth.”
Carl Sagan
Evidence
The available body of facts or information
indicating whether a belief or proposition is
true or valid” .
Evidence-based Medicine
apply the best available evidence gained from the scientific
method to clinical decision making
assess the strength of evidence of treatments and diagnostic
tests.
Evidence quality can range from meta analyses and systematic
reviews of double blind, placebo-controlled clinical trials at the
top end, down to conventional wisdom at the bottom.
Emerge of Evidence-Based Medicine
First described in 1992
A new approach to teaching medicine
A “revolution” in medical practice
Other “evidence-based” approaches: ethics,
psychotherapy, occupational therapy, dentistry,
nursing, and librarianship
Driving Factors of EBM
Overwhelming size of the literature
Inadequacy of textbooks
Difficulty synthesizing evidence and translating
into practice
Increased number of RCTs
Available computerized databases
Reproducible evidence strategies
Definition of EBM
“ The integration of best research evidence
with clinical expertise and patient values.”
Steps of EBM
►Convert the need for info. into an answerable
question
►Track down the best evidence
►Critically appraise that evidence
►Integrate the appraisal with one’s clinical expertise
and the individual patient
►EvaluateSackett DL. EBM: how to practice and teach EBM. Churchill Livingstone 2000
Critique of EBM
De-emphasizes patient values
Doesn’t account for individual variation
Devalues clinical judgment
Leads to therapeutic nihilism
Evidence-based Public Health
Definition: “the development, implementation, and
evaluation of effective programs and policies in
public health through application of principles of
scientific reasoning, including systematic uses of
data and information systems, and appropriate use of
behavioral science theory and program planning
models”
Source: Brownson, R.C. et al, Evidence-based public health, Oxford University Press, 2003.
Development of EBPH
Jenicek (1997) published a review discussing
epidemiology, EBM, EBPH
Epidemiology described as the foundation of
both EBM and EBPH
EBPH unique in using complex interventions
with multiple community and societal issues
Steps of EBPH
► Develop an initial statement of the issue
► Search the scientific literature and organize
information
► Quantify the issue using sources of existing data
► Develop and prioritize program options; implement
interventions
► Evaluate the program or policy
EBM and EBPH Parallels
State the scientific question of interest
Identify the relevant evidence
Determine what information is needed to
answer the scientific question
Determine the best course of action
considering the patient or population
Evaluate process and outcome
Differences between EBM and EBPH
Characteristic Evidence-Based Medicine
Evidence-Based Public Health
Quality of evidence Experimental studies Observational and quasi-experimental studies
Volume of evidence Larger Smaller
Time from intervention to outcome
Shorter Longer
Professional training of workforce
More formal, with certification and /or licensing
Less formal, no standard certification
Decision making Individual Team
Steps in the EBPH Process1. Define a public health problem;
2. Identify information to solve problems;
3. Searching the literature;
4. Critical appraisal of the evidence;
5. Selecting the best evidence for a public health decision;
6. Linking evidence with public health experience, knowledge, practice,
and the community’s values and preferences;
7. Implementing findings in public health practice and programs
(intervention);
8. Evaluating results.
Source: Jenicek, Milos and Sylvie Stachenko. 2003. Evidence-based public health, community medicine, preventive care. Medical Science Monitor: 9(2): p, SR2.
Evidence-Based Public Health
Define the issue
Quantify the issue Conduct literature
review
Develop program or policy options
Develop planEvaluate the
program or policy
Steps in Searching the Public Health Literature
1. Determine the public health problem and define the
question
2.Select information sources
3.Identify key concept and terms
4.Conduct the search
5.Select documents for review
6.Abstract relevant information from the documentation
7.Summarize and apply the literature review
Source: Adapted from Brownson. Evidence-based public health. Oxford University Press, 2003, p. 128.
Appraising the Evidence & Evaluating the Results
What are the results?
Are the results valid?
How can the results be applied to public
health practice and interventions?
Source: Guide to Research Methods: The Evidence Pyramid: <http://servers.medlib.hscbklyn.edu/ebm/2100.htm>.
Hierarchy of Research Designs
Category I: Evidence from at least one properly
randomized controlled trial.
Category II-1: Evidence from well-designed controlled
trials without randomization.
Category II-2: Evidence from well-designed cohort or case-
control analytic studies, preferably from more than one
center or research group.
Category II-3: Evidence from multiple times series with or
without intervention or dramatic results in uncontrolled
experiments such as the results of the introduction of
penicillin treatment in the 1940s.
Category III: Opinions of respected authorities, based on
clinical experience, descriptive studies and case reports,
or reports of expert committees.
Source: Harris, R.P. et al. (2001). Current methods of the U.S. Preventive Services Task Force: a
review of the process. American Journal of Preventive Medicine. April 20 (3 Supplement): 21-
35
Types of Evidence
Systematic Review: critical assessment and evaluation of research
that attempts to address a focused question using methods designed to reduce
the likelihood of bias.
Meta-Analysis: overview that incorporates a quantitative strategy for
combining the results of several studies into a single pooled or summary
estimate.
Risk Assessment: systematic approach to characterizing the risks
posed to individuals and populations by environmental pollutants and other
potentially adverse exposures.
Decision Analysis: systematic approach to decision making under
conditions of uncertainty; involves identifying all available alternatives and
estimating the probabilities of potential outcomes associated with each
alternative, valuing each outcome, and, on the basis of the probabilities and
values, arriving at a quantitative estimate of the relative merit of the alternatives.
Economic Evaluation: comparative analysis of alternative courses
of action in terms of both their costs and consequences.
Expert Panels: examination of research studies and their relevance to
health conditions, diagnostic and therapeutic procedures, planning and health
policy, and community interventions.
Practice Guidelines: systematically developed statements to
assist practitioner and patient decisions about appropriate health care for
specific clinical circumstances; may be developed by government agencies,
institutions, or by the convening of expert panels.
Source: R.C. Brownson et al, Evidence-Based Public Health, Oxford: Oxford University, 2003.
Evidence spectrum
Meta analysis/ Systematic review/ Evidence-based guidelines
Weak Strong
No evidence/ case reports
Best PracticesLocal needs assessment
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
The problem of randomized trials and parachutes….
PubMed <www.pubmed.gov>
Cochrane Collaboration www.cochrane.org
TRIP Database www.tripdatabase.com/
NICHSR: National Information Center on Health Services Research &
Health Care Technology http://www.nlm.nih.gov/nichsr/nichsr.html
Partners in Information Access for the Public Health Workforce
<phpartners.org> Lamar Soutter Library: EBPH Project
<http://library.umassmed.edu/ebpph/>
Best Evidence Resources
Step 1: Determine/Define the question (Evidence types)
Type 1 Something should be done
Type 2 This should be done
Type 3 How the intervention should be done
Step 1: Determine/Define the question
P =Patient/Population/Problem
I =Intervention/Item of interest
C =Comparison
O =Outcome
You coordinate social activities for a few of the city’s senior
centers. The latest Behavioral Risk Factor Surveillance System
(BRFSS) survey showed that seniors in your state are not
participating in regular exercise or many other health promotion
behaviors. You’ve heard that physical activities for older adults
can have a host of benefits, and would like to submit a grant to
begin an exercise program. You must find literature supporting
the effect of exercise programs in reducing injuries or decreasing
risk of chronic disease in the elderly.
A Scenario
P
I
O
C – no comparison/placebo
I
P = inactive seniors
I = community exercise programs
C = no comparison
O = reduced injuries/chronic disease
PICO
The question…
In inactive senior populations, are formal
exercise programs effective in reducing
injuries and chronic disease associated with
the aging process?
Step 2: Select information sources
Systematic Reviews and Meta-analyses
Practice Guidelines
Journal Literature
Best Practices
Step 3: Identify key concept and terms
In inactive senior populations, are formal
exercise programs effective in reducing
injuries and chronic disease associated with
the aging process?
P = inactive seniors I = community exercise programs C = no comparison O = reduced injuries/chronic disease
Step 3: Identify key concepts and terms
PSeniors/senior
citizenselderlyaged
Iexercisephysical activityrecreation
program developmentprogram evaluationeffective programs