Using Evidence To Improve Public Health Infrastructure:

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(No Transcript)
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• Using Evidence To Improve Public Health
  Infrastructure
• Let the evidence guide our actions

January 7, 2004 Jonathan E.
Fielding, M.D., M.P.H., M.B.A Director of Public
Health and Health Officer L.A. County
Department of Health Services Chair, CDC Task
Force of Community Preventive Services Professor
of Public Health and Pediatrics University of
California, Los Angeles
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If we did not respect the evidence, we would have
very little leverage in our quest for truth

• Carl Sagan

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Quality of the Evidence

• We hear about it often
• TV Networks
• Usually related to high profile trials
• Public Health evidence is different than legal
  evidence
• It is the available information on a particular
  question
• We want the best available evidence in making
  decisions

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Decisions and Evidence

• Evidence takes many forms
• Opinion of leaders
• Opinion of experts
• Studies without controls
• Studies with controls
• Studies of variable quality in design and
  execution

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Decisions and Evidence

• Our commitment
• Improve public health
• Health problems well defined
• Our job
• Make a difference through policies and programs
• Inaction is not an option
• Hard to identify best evidence to inform decision
  making

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Decisions and Evidence

• Decisions on policies and programs are often made
  based on
• Personal experience
• What we learned in formal training
• What we heard at a conference
• What a funding agency required/ suggested
• What others are doing

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Evidence and Public Health Decision Making

• Good news
• Strong evidence on the effect of many policies/
  programs aimed to improve public health
• Major efforts underway to assess the body of
  evidence for wide range of public health
  interventions

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What works to improve the publics health?

• Bad news
• Many public health professionals are unaware of
  this evidence
• Some who are aware dont use it
• Many existing disease control programs have
  interventions with insufficient evidence while
  others use interventions with strong evidence of
  effectiveness
• Lack of use of effective interventions can
  adversely affect fulfilling mission and getting
  public support

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How do we know what works in improving the health
of populations?

• Background
• Many community health improvement efforts have
  not achieved desired results
• Interventions often chosen based on opinions and
  personal preferences
• Evidence based medicine---Clinical Preventive
  Services Task Force mid 80s
• Evidence based population health --- Community
  Preventive Services Task Force mid 90s

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Systematic Search for the Best Evidence

• U.S. Community Preventive Services Task Force
  Appointed by CDC Director in 1996
• Non-Federal independent task force of experts in
  multiple relevant disciplines
• Epidemiology
• Public Health Practice
• Behavioral Sciences
• Evidence based medicine/ public health
• Other relevant areas of expertise

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Goals

• Conduct careful analytic reviews of acceptable
  evidence for population health interventions and
  make related recommendations
• Use peer reviewed literature
• Standard rules of evidence
• Standard rules for translating evidence into
  recommendations for interventions

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Systematic Reviews of Public Health Interventions
are Useful

• Methods first developed by social scientists
  (e.g., Glass, 76)
• Distill and summarize large and diverse bodies of
  evidence
• Reduce errors and biases in interpretation
• Make assumptions explicit

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Systematic Reviews Are Not

• Limited to randomized controlled trials
• Limited to healthcare interventions
• Restricted to a biomedical model of health
• - Petticrew, 2001

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Task Force on Community Preventive Services
Members

• George J. Isham
• Robert L. Johnson
• Garland Land
• Patricia A. Nolan
• Dennis E. Richling
• Barbara K. Rimer
• Steven Teutsch

• Jonathan E. Fielding, Chair
• Patricia Dolan Mullen, Vice-chair
• Noreen M. Clark
• John M. Clymer
• Mindy T. Fullilove
• Alan Hinman

Consultants Robert S. Lawrence J. Michael
McGinnis Lloyd F. Novick
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Who Is the Audience?

• People who plan, fund, or implement public health
  services and policies for communities and
  healthcare systems
• Public health departments
• Healthcare systems and providers
• Purchasers
• Government agencies
• Community organizations

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Community Guide Topics
Environmental Influences Environmental Influences
Sociocultural Environment Sociocultural Environment
Physical Environment Physical Environment
Risk Behaviors Specific Conditions
Tobacco Use Alcohol Abuse/Misuse Other Substance Abuse Poor Nutrition Inadequate Physical Activity Unhealthy Sexual Behaviors Vaccine Preventable Disease Pregnancy Outcomes Violence Motor Vehicle Injuries Depression Cancer Diabetes Oral Health
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Methods for Systematic Reviews of Effectiveness
Evaluations

• Develop conceptual framework
• Search for and retrieve evidence
• Rate quality of evidence
• Summarize evidence
• Translate strength of evidence into finding
• Strongly recommended
• Recommended
• Insufficient evidence

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Logic Framework Vaccine Preventable Disease
Treatment
Increasing
Provider-
Enhancing
of Vaccine-
Community
Access to
Based
Demand for
Preventable
Interven tions
Vaccina tions
Diseases
Vaccinations
Vaccine-
Attendance in
Morbidity
Public, Private, or
Preventable
and
Population
Joint Healthcare
Disease
Mortality
Systems
Vaccination
Coverage
Intervention Types
Determinants

Exposure to
Intermediate Outcomes
Vaccine-
Environment
Preventable
Disease
Public Health Outcomes
Reviewed
Reducing
Not Reviewed
Exposure
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Standardized Analysis Process

• Systematic review of literature
• Abstracting of relevant studies
• Grading of evidence
• Study design
• Execution
• Translating from quality of evidence to
  recommendations
• Economic analysis
• Other benefits and harms

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How Does the Task Force Define Suitability of
Study Design?

• Greatest
• Prospective with concurrent comparison
• Moderate
• Multiple before-and-after measurements but no
  concurrent comparison OR
• Retrospective
• Least
• Single group before-and-after
• Cross-sectional

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What Factors Determine Quality of Execution?

• Description of intervention and study population
• Sampling procedures
• Exposure and outcome measurements
• Approach to data analysis
• Interpretation of results
• Follow-up
• Confounding
• Other bias
• Other issues

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How Does the Task Force Draw an Overall
Conclusion About the Strength of a Body of
Evidence?

• Number of studies
• Design suitability
• Quality of execution
• Consistency
• Effect size

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Evidence of Effectiveness Quality of Execution Design Suitability Number of Studies Consistent Effect Size
Strong Strong Strong Strong Strong Strong
Good Greatest gt 2 Yes Sufficient
Good Greatest or Moderate gt 5 Yes Sufficient
Good or Fair Greatest gt 5 Yes Sufficient
Meet criteria for sufficient evidence Meet criteria for sufficient evidence Meet criteria for sufficient evidence Meet criteria for sufficient evidence Large
2. Sufficient 2. Sufficient 2. Sufficient 2. Sufficient 2. Sufficient 2. Sufficient
Good Greatest 1 -- Sufficient
Good or Fair Greatest or Moderate gt 3 Yes Sufficient
Good or Fair Greatest, Moderate or Least gt 5 Yes Sufficient
3. Insufficient Insufficient design or execution Insufficient design or execution Too few No Small
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Physical ActivityReview of One Intervention

• Goal increase the amount of time students spend
  doing moderate or vigorous activity in PE class
  through curricular change
• Interventions reviewed included changing the
  activities taught (e.g., substituting soccer for
  softball) or modifying the rules of the game so
  that students are more active (e.g., in softball,
  have the entire team run the bases together when
  the batter makes a base hit). Many interventions
  also included health education.

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School Curricular Interventions to Improve
Physical Fitness

• 14 acceptable studies in all students physical
  fitness improved.
• 5 studies measured activity levels during PE
  class all found increases in
• amount or percentage of time moderately/
  vigorously active and/or
• intensity level of physical activity during
  class.
• Median estimates--modifying school PE curricula
  as recommended will result in an 8 increase in
  aerobic fitness

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School Curricula to Improve Physical Activity

• Modifying school P.E. curricula was effective
  across diverse racial, ethnic, and socioeconomic
  groups, among boys and girls, elementary- and
  high-school students, and in urban and rural
  settings.
• In a separate literature review, having students
  attend school PE classes was not found to harm
  academic performance.
• Economic analysis pending.