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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




Anatomy of a Clinical Question (PICO)

1. Patient or problem

How would you describe a group of patients similar to yours? What are the most important characteristics of the patient? This may include the primary problem, disease, or co-existing conditions. Sometimes the sex, age or race of a patient might be relevant to the diagnosis or treatment of a disease.

2. Intervention, prognostic factor, or exposure

Which main intervention, prognostic factor, or exposure are you considering? What do you want to do for the patient? Prescribe a drug? Order a test? Order surgery? What factor may influence the prognosis of the patient? Age? Co-existing problems? What was the patient exposed to? Asbestos? Cigarette smoke?

3. Comparison

What is the main alternative to compare with the intervention? Are you trying to decide between two drugs, a drug and no medication or placebo, or two diagnostic tests? Your clinical question does not always need a specific comparison.

4. Outcomes

What can you hope to accomplish, measure, improve or affect? What are you trying to do for the patient? Relieve or eliminate the symptoms? Reduce the number of adverse events? Improve function or test scores?

The PICO structure of the question might look like this:

Patient / Problem

stroke, without dysphagia, elderly


oral protein energy supplements added to usual hospital diet

Comparison, if any

none, placebo added to usual hospital diet


primary: reduce mortality; secondary: reduce serious disability risk over time


For our patient, the clinical question might be:

In an elderly patient with a stroke, without dysphagia or trouble eating, does adding oral protein energy supplements to the usual hospital diet decrease the risk of death or serious disability over a period of several months?


We now go to the next section, Finding Evidence: Selecting a Resource







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