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Center for Health Sciences
Medical Physiology - Evidence-Based Medicine
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What is EBM?

Patient Care Model
Life-long Learning
Why is EBM Important?
Available Evidence?
EBM Issues

The Well-built Question

The EBM Process
Anatomy of a Question

Finding Evidence

Selecting a Resource
Searching the Resource
Reviewing Search Results
Returning to the Patient

Evaluating Evidence

Evaluating the Validity
Validity Questions


Knowledge Test

Multiple Sclerosis
Case #2
Case #3
Case #4




Why Is EBM Important?

Clinicians want to practice the best medicine possible. EBM facilitates this by providing an effective, efficient framework for seeking, appraising and implementing evidence for patient care.

Studies of information-seeking habits of physicians, have shown that when asked:

  • Physicians reported that their practice generated about 2 questions for every 3 patients
  • Only 30% of physicians' information needs were met during the patient visit, usually by a colleague

Reasons for not using printed resources included:

  • Office textbook collections too old
  • Lack of knowledge of appropriate resources
  • Lack of time to find the needed information

    (Covell DG, 1995)

When actually observed, investigators found that:

  • Physicians had about 5 questions for each patient
  • 52% of these question could be answered by the medical record or hospital information system.
  • 25% could have been answered by published information resources such as textbooks or MEDLINE

    (Osheroff JA, 1991)

However, studies have also shown that when clinicians have access to information, it changes their patient care management decisions.

In 1998, Dr. David Sackett, using an "evidence cart" on rounds, reported that of 71 information searches to answer clinical questions:

  • 37 (52%) confirmed the management decision
  • 18 (25%) lead to a new therapy or diagnostic test
  • 16 (23%) corrected a previous plan

    (Sackett D, 1998)

Similar results were report by Crowley et al in 2003. The CAR study showed that of 520 clinical questions for which answers were sought in the medical literature:

  • In 53% of these cases the literature confirmed the management decision
  • In 47% of these cases the literature changed the medication, diagnostic test, or prognostic information given to the patient

    (Crowley S, 2003)


We now go to Is Evidence Available?