Transcript An Introduction to Evidence

An Introduction to EvidenceBased Public Health
Neal D. Kohatsu, MD, MPH
Associate Professor
Dept. of Epidemiology
Case Presentation
Case Presentation
• Assume that you are the health director
of a local health department.
• A community in your jurisdiction is
concerned with its high rate of childhood
obesity and requests your help.
• How do you proceed?
Overview
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Rise of evidence-based medicine
Development of evidence-based PH
Current perspective on PH
New definition of EBPH
Evaluating and improving EBPH
Review of case presentation
Summary
Rise of Evidence-Based Medicine
Rise of Evidence-Based Medicine
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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
Factors Driving EBM
Factors Driving 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.”
Sackett DL et al; Churchill Livingstone,
2000
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
• Evaluate
Sackett DL. EBM: how to practice and teach EBM.
Churchill Livingstone 2000
Critique of EBM
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De-emphasizes patient values
Doesn’t account for individual variation
Devalues clinical judgment
Leads to therapeutic nihilism
Parachute use to prevent death and major trauma
related to gravitational challenge; systematic review of
randomised controlled trials.
Smith GC, Pell JP. BMJ 327:1459-1461; 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
Definition of EBPH (1)
• “EBPH is the conscientious, explicit,
and judicious use of current best
evidence in making decisions about the
care of communities and populations in
the domain of health protection,
disease prevention, health maintenance
and improvement.”
Jenicek (1997)
Jenicek M. J Epidemiol 1997;7:187-97
Definition of EBPH (2)
• “EBPH is 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 program planning models.”
Brownson (1999)
Brownson RC. J Public Health Manag
Pract 1999;5:86-97
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
Brownson RC. J Public Health Manag
Pract 1999;5:86-87
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
• Evaluate
Sackett 2000
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
Kohatsu et al. Am J Prev Med
2004;27:417-21
Cochrane Collaboration
Mission:
“…an international organisation that
aims to help people make well-informed
decisions about health care by
preparing, maintaining and promoting
the accessibility of systematic reviews
of the effects of healthcare
interventions.”
www.cochrane.org
Structure of the Collaboration
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Collaborative Review Groups
Methods Groups
Fields
Consumer Network
Centres
Guide to Community Preventive
Services
• Developed by the U.S. Task Force on
Community Preventive Services
• Supported by the U.S. Centers for
Disease Control and Prevention (CDC)
• Based on systematic reviews
• Recommendations based on strength
of evidence
Briss PA et al. AJPM 2000;18(1S):35-43.
Topic Areas
• Vaccine-preventable
diseases
• Tobacco use
prevention and
control
• Reducing motor
vehicle occupant
injury
• Diabetes
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Physical activity
Oral health
Social Environment
Prevention of injuries
due to violence
• Cancer
A Current Perspective on PH
• Public health encompasses:
“the efforts, science, art, and approaches
used by all sectors of society to assure,
maintain, protect, promote, and
improve the health of the people.”
The future of the public's health in the 21st
century. IOM 2002.
Public Health
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Communities
Healthcare system
Employers & business
Media
Academia
Government
IOM, 2002
Definition of EBPH (3)
• “The process of integrating sciencebased interventions with community
preferences to improve the health of
populations.”
Kohatsu, Robinson, Torner. AJPM
2004;27:417-21.
The Future of Evidence-Based
Public Health
• How can we evaluate and improve
EBPH in practice?
Improving EBPH in Practice
• Quality of the Science Base
• Community Involvement
• Effect on Public Health Outcomes
Improving the Quality
of the Science Base
• Moving beyond RCTs
• Transparent Reporting of Evaluations
with Non-randomized Designs (TREND)
• Grading of Recommendations
Assessment, Development and
Evaluation (GRADE)
Improving Community Involvement
Improving Community Involvement
• “Public health institutions should
provide communities with the
information they have that is needed
for decisions on policies or programs
and should obtain the community’s
consent for their implementation.”
--Public Health Leadership Society
www.phls.org
Informed Consent at the
Community Level
• Community-based participatory
research
• Community advisory boards
Improving EBPH Outcomes
• Difficult to assess
• Issues of sample size, contamination,
blinding, long-term follow-up
• Ethical constraints of withholding
evidence
• Patients do better in the “real world”
when provided with evidence-based
therapy
Case Presentation
• Assume that you are the health director of
a local health department.
• A community in your jurisdiction is
concerned with its high rate of childhood
obesity and requests your help.
• How do you proceed?
Develop an Initial
Statement of the Issue
• The prevalence of obesity among the
327 elementary school children in the
community is 35%. With the support of
parents, school staff, and communitybased organizations, how can this
obesity rate be reduced through
lifestyle interventions?
Quantify the Issue
• The prevalence of obesity was
determined by a special survey.
• The rate of obesity was found to
increase by grade level.
• The rates were about equal in girls and
boys.
• 100 minutes/wk provided at school for
physical activity, but only 40 minutes is
guided by a teacher.
Search the Scientific Literature
and Organize Information
• Medline search
• Cochrane Collaboration
• Task Force on Community Preventive
Services
Task Force on Community
Preventive Services
• Insufficient evidence to recommend
classroom-based health education to
provide information on managing
health risks.
• Strongly recommended curricula and
policies to increase the amount of
moderate or vigorous activity, increase
the amount of time in PE class, or the
amount of time being active in PE.
MMWR 2001;50, No. RR-18
Develop and Prioritize
Program Options
• A community-based work group
develops a number of options to
increase physical activity in school.
• There are debates about losing time in
the classroom and impact on test
performance.
Develop an Action Plan
Develop an Action Plan
• Agreement is reached on a pilot project
for the next school year involving
reducing the lunch hour and increasing
time in physical education with an
emphasis on activities that get all
children to be active.
• The program will be evaluated by all
stakeholders (e.g., children will be
surveyed)
Summary
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EBM has transformed medicine
EBM has fostered development of EBPH
EBPH continues to evolve
Increased community engagement