Evidence-Based Medicine:What does it really mean?

Sports Medicine Rounds

November 7, 2007

What is Evidence-Based Medicine?

• A Philosophical Framework?

• An Evolving Concept?

• A Method of Practice?

• A Quality Improvement Approach?

• A Teaching Tool?

• A Potentially Dangerous Thing if used Incorrectly?

ALL OF THE ABOVE

A New Concept?

• The concept of modifying clinical practice based on research results has been in place for hundreds, perhaps thousands of years

• In the 20th century (1990’s+) it has evolved to impact almost all fields of healthcare and policy; a structured approach

Largely Developed by One Group

The specific methodologies used to determine “best evidence” were largely established by a research group led by David Sackett & Gordon Guyatt at McMaster U.

“Evidence-based medicine is the conscientious, explicit, & judicious use of current best evidence in making decisions about the care of individual patients” David Sackett, 1996

What is Evidence-Based Medicine?

“The integration of best research evidence with clinical expertise & patient values”

Sackett et al, 2000

What is Evidence-Based Medicine?

Types of Evidence-Based Medicine

• Evidence-based guidelines (EBG): practice of EBM at the organizational, institutional, or group level (establishing guidelines, policy, regulations)

Types of Evidence-Based Medicine

• Evidence-based individual decision making (EBID): EBM as practiced by the individual healthcare provider in determining how to treat patients

Some are suggesting we may betoo EBM focused

Evidence-Based Medicine: A Process

1. Identify a patient-oriented/practice-oriented problem that is of interest

2. Develop a specific clinical question that targets the problem

3. Review the available evidence

4. Appraise the evidence → Decision

5. Integrate the evidence into your practice

6. Assess your outcomes (if appropriate)

• Important not to confuse Levels of Evidence with Quality of Evidence or Importance

An Idealistic EBM Model

Study Design Should Match “?”

• RCT: Homogeneous patients randomized to intervention A or B & compare outcomes

• Longitudinal Cohort: Compare a group of people with a risk factor over time to see who develops a disease/injury; prognosis

Study Design Should Match “?”

• Case-Control: People with condition are compared to those without on a set of variables to assess effect(s) or associations with variables; Diagnostic or descriptive

• Cross-sectional Survey: A sample from a population is assessed for a certain disease/finding and specific risk factors at that single point in time; descriptive

Systematic Reviews & Meta-analyses

• Systematic Review:

• Structured review of the literature

• Set inclusion & exclusion criteria

• Assess study design quality

• Assess methodological quality (rarely)

• Compile & summarize results

• Goal: determine what the current evidence is on a specific topic

Systematic Reviews & Meta-analyses

• Meta-Analysis:

• Also a structured review of the literature

• Set inclusion & exclusion criteria

• Assess study design quality

• Assess methodological quality (rarely)

• Perform statistics on the integrated results of the grouped studies

• Goal: draw conclusions from the results of the analysis of the grouped data

Systematic Reviews

• Goal: Summaries of best evidence; information overload

• Top level of evidence; everyone doing them

• Most are fair in terms of value

• Over 1.3 Million listed in MEDLINE alone

• About 5000 on the knee alone

• Need to evaluate carefully

Systematic Review Killers

• Low level research / Lack of Research

• Heterogeneity of subject pools

• Heterogeneity of methodology

• Lack of detail prohibits comparison

• Authors are often knowledgeable on general topic & evaluating study design & sources of bias, but not intervention methods

Must be Savvy Consumers of the Scientific Literature

• Cannot just read abstract, conclusions, & look at figures

• Hypotheses, methods, & results are most important

• Design appropriate?

• Bias?

• Conclusion based on results & consistent with methods?

Things to Consider

• EBM is only as good as the data available

• A quality case-control study is more meaningful than a flawed RCT

• Thus, systematic reviews of RCTs are not necessarily best evidence

Final Thoughts

• Payers have also adopted this

• Lack of evidence is being equated with lack of benefit; this is not true (call for evidence)

• There are other clinical decision-making approaches

• There are highly reputed health care experts who are stark opponents to the EBM approach accepted by most

Patient-Based Outcomes Measures

• What do they tell us?

• Does the KOOS QOL tell us someone’s knee is healthy?

• Can it tell us how well someone is doing or does it simply tell us if there is noteworthy disability or not?

• Is the difference between an 80 & 88 on the score the same as 88 to 96?

• What is a good score? In a young athlete?