Answering a clinical question according to the Evidence-Based Medicine (EBM) method involves a systematic literature search to locate the best scientific evidence.
On the basis of the evidence found, an answer to the question is formulated.
This answer, together with clinician's expertise and patient's preferences/values, can be used in taking clinical decisions.
For clinical search questions, different research databases may be used, such as:
(in pink: the steps that are supported by University Library Utrecht)
In principle, a good systematic review (for instance in Cochrane Library) has the highest level of evidence.
Critically Appraised Topics (CATs, for instance in BMJ Clinical Evidence) are often less extensive in scope than systematic reviews; when carefully carried out, they provide good quality of evidence.
The quality of evidence of individual studies (for instance in PubMed) varies with the type of study: randomized controlled trials (RCTs) have a higher quality of evidence than cohort studies, but are often only available for therapeutic questions.
Please note: Guidelines are often a combination of evidence-based recommendations and expert opinion.
Different terms are used to denote answering a clinical question using the EBM-method:
CAT: Critically Appraised Topic. The CAT is a compulsory part of the training program of medical specialists (AIOS)
PICO: an abbreviation of the different parts of a clinical question ((Patient-Intervention-Comparison-Outcome), but is sometimes used as a synonym for CAT.
Question of the week: the interpretation given to the CAT within the department Internal Medicine in UMC Utrecht.