Evidence-Based Medicine Tutorial

Definition of Evidence-Based Medicine

Evidence based medicine (EBM) was originally defined as the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research.
(Sackett DL, Rosenberg WMC, Gray JAM, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn't. BMJ 1996; 312: 71-2)

The revised and improved definition of evidence-based medicine is a systematic approach to clinical problem solving which allows the integration of the best available research evidence with clinical expertise and patient values.
(Sackett DL, Strauss SE, Richardson WS,et al. Evidence-based medicine: how to practice and teach EBM. London: Churchill-Livingstone,2000)

Evidence-Based Practice is defined as, "Making a conscientious effort to base clinical decisions on research that is most likely to be free from bias, and using interventions most likely to improve how long or well patients live." 
(Mark H. Ebell, MD, MS, Professor, University of Georgia, Editor-in-Chief, Essential Evidence Plus)

What EBM skills do all practicing clinicians really need?

While EBM is a large step forward, these skills are necessary but not sufficient for the practice of contemporary medicine. All clinicians should:

  • Find the best evidence for every day practice (Information mastery)
  • Assess relevance before rigor. Is the evidence patient oriented?
  • Evaluate information about therapies, diagnostic tests, and clinicaldecision rules. Is it true?
  • Understand basic statistics.
  • Have at fingertips "just in time" information at the point of care using web based and/or handheld computer based information and tools for clinical decision making
  • Evaluate expert-based information, including colleagues, CME, presentations, reviews and guidelines.
  • Critically evaluate information from pharmaceutical representatives. No Free Lunch.

Slawson DC, Shaughnessy AF. Teaching evidence-based medicine: should we be teaching information management instead? Acad Med. 2005 Jul;80(7):685-9.

EBM as Lifelong Learning

The practice of evidence-based medicine is a process of lifelong, self-directed, problem-based learning in which caring for one's own patients creates the need for clinically important information about diagnosis, prognosis, therapy and other clinical and health care issues.

Instead of routinely reviewing the contents of dozens of journals for interesting articles, EBM suggests that you target your reading to issues related to specific patient problems. Developing clinical questions and then searching current databases may be a more productive way of keeping current with the literature.

Evidence-based medicine "converts the abstract exercise of reading and appraising the literature into the pragmatic process of using the literature to benefit individual patients while simultaneously expanding the clinician's knowledge base."
(Bordley, D.R. Fagan M, Theige D. Evidence-based medicine: a powerful educational tool for clerkship education. Am J Med. 1997 May;102(5):427-32.)

EBM as Patient Centered Care

Decision Making and the Patient.  Ch 27, Users' Guides to the Medical Literaturs.  JAMAevidence.

Shared Decision Making: A Model for Clinical Practice. Journal of General Internal Medicine. 2012;27(10):1361-1367.

Mayo Clinic Shared Decision Making National Resource Center

Directory of Decision Aids at the Ottawa Hospital Research Institute

Five Step Model of Evidence-Based Medicine

  1. Convert information needs into answerable questions
  2. Track down with maximum efficiency the best evidence with which to answer them
  3. Critically appraise that evidence for its validity and usefulness
  4. Apply the results of this appraisal in your practice
  5. Evaluate your performance

To convert your information needs into a focused question, PICO format, see:

Levels of Evidence

Levels of Evidence

Ebell MH, Siwek J, Weiss BD, et al. Strength of recommendation taxonomy (SORT): a patient-centered approach to grading evidence in the medical literature. Am Fam Physician. 2004 Feb 1;69(3):548-56.

The EBM Pyramid hierarchy of rigor

Major Evidence Based Medicine Databases (EBM Foraging Tools)

A high-quality foraging tool employs a transparent process that

  1. systematically surveys or reviews the literature,
  2. filters out disease-oriented research and presents only patient-oriented research outcomes,
  3. demonstrates that a validity assessment has been performed using appropriate criteria,
  4. assigns levels of evidence, based on appropriate validity criteria, to individual studies,
  5. provides specific recommendations, when feasible, on how to apply the information, placing it into clinical context,
  6. comprehensively reviews the literature for a specific specialty or discipline, and
  7. coordinates with a high-quality hunting tool.
    (Slawson, et al)

Cochrane Collaboration.
Highest level of rigor, systematically reviews the entire English publications on a topic. Full text available through Cochrane Library . Cochrane Systematic Reviews on therapy topics only contain randomized clinical trials. (What is the Cochrane Collaboration?)

ACP Journal Club
Critical appraisals of studies from two journals, the ACP Journal Club and Evidence Based Medicine.

Evidence-Based Practice
Journal published by FPIN, Family Physicians Inquiries Network, containing reviews of current research.

Patient Oriented Evidence that Matters. Published daily. Ongoing since 1996, editors review more than 1,200 studies monthly from 100+ medical journals, presenting only the best as InfoPOEMs. The acclaimed POEMs process applies specific criteria for validity and relevance to clinical practice. About 1 in 40 studies qualifies. (What is an InfoPOEM?)

National Guideline Clearinghouse
Storehouse of most clinical practice guidelines, some evidence-based, some specialty based, from the AHRQ.

US Preventative Services Task Force
An independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services.
Use online ePSS Tool

EBM Hunting Tools

These resources combine many of the above resources into one tool that searches multiple resources, then organizes the results by category representing the type of question you have. Four of the following are available on the web and PDA for all CoM faculty and students. Step-by step-directions for using each of these products on the web and PDA is available in this PDF document: Using EBM Resources

Essential Evidence Plus
Collection of systematic review, calculators, and other evidence based resources. Includes the Cochrane abstracts, InfoPOEM reviews, guidelines, clinical prediction tools, Essential Evidence and much more. Available on PDA.

DynaMed contains clinically organized summaries of nearly 1,800 topics and is updated daily from review of the research literature. Includes the Cochrane abstracts, ACP Journal Club, guidelines, USPSTF recommendations, their own reviews, as well as background materials. Available on PDA.

See EBM Tools on the Medical Library Website.

Last resort to track down evidence. Articles will need to be appraised before using.


Advanced EBM Skills

Only a small percentage of clinicians in each specialty need to be able to do the following:

  • Critical Appraisal and Interpretation of Research on:
    • Therapies
    • Diagnostic Tests
    • Prognosis
  • Critical Evaluation and Interpretation of:
    • Systematic Reviews, Including Meta-analysis
    • Decision Analysis
    • Practice Guidelines
    • Pharmaceutical Advertising, Including Pharmaceutical Representatives
  • Assigning Levels of Evidence to Research Findings to:
  • Teaching Level 1 Skills
  • Written Communication of Research Findings
    • Physicians
    • Patients

(Slawson, et al)

To help critically appraise an article or guideline, use the following guides:

Users' Guides to the Medical Literature
User guides to evidence-based practice from JAMA.

How to Read A Paper (series in BMJ) by Trisha Greenhalgh

Critical Appraisal Worksheets

Study design, statistics and levels of evidence

More information about evidence-based medicine