An Introduction to Evidence-Based 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

• 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

• 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

Sackett DL et al; Churchill Livingstone, 2000

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

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

Jenicek M. J Epidemiol 1997;7:187-97

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)

Brownson RC. J Public Health Manag Pract 1999;5:86-97

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;5:86-87

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

Sackett 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

Kohatsu et al. Am J Prev Med 2004;27:417-21

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

www.cochrane.org

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.”

Structure of the Collaboration

• Collaborative Review Groups

• Methods Groups

• Fields

• Consumer Network

• Centres

Briss PA et al. AJPM 2000;18(1S):35-43.

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

Topic Areas

• Vaccine-preventable diseases

• Tobacco use prevention and control

• Reducing motor vehicle occupant injury

• Diabetes

• Physical activity• Oral health• Social Environment• Prevention of injuries

due to violence• Cancer

The future of the public's health in the 21st century. IOM 2002.

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.”

IOM, 2002

Public Health

• Communities

• Healthcare system

• Employers & business

• Media

• Academia

• Government

Kohatsu, Robinson, Torner. AJPM 2004;27:417-21.

Definition of EBPH (3)

• “The process of integrating science-based interventions with community preferences to improve the health of populations.”

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 Qualityof 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

www.phls.org

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

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 InitialStatement 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 community-based 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

MMWR 2001;50, No. RR-18

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.

Develop and PrioritizeProgram 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

• EBM has transformed medicine

• EBM has fostered development of EBPH

• EBPH continues to evolve

• Increased community engagement