Mayo Clinic Medical Science Blog
A team of international experts led by a Mayo Clinic researcher has published in the Journal of the American Medical Association a guide for clinicians who are interested in using systematic reviews and meta-analysis in clinical decision making. This article is the latest in the well-known series of users’ guides to the medical literature that JAMA started publishing in the mid 1990s and is highly sought after by clinicians who want to learn and practice evidence based medicine. “When searching for evidence to answer a clinical question, it’s better to seek a systematic review, especially one that includes a meta-analysis,” says M. Hassan Murad, M.D., Knowledge Synthesis Program, Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery. “Single studies are liable to be unrepresentative of the total evidence and can be misleading.” Systematic reviews include a greater range of patients than any single study, while meta-analysis of a body of evidence includes a larger sample size and more events than any individual study, the authors note. They recommend that providers assess these studies by using two judgments: First judgment: Evaluate the credibility of the methods of the systematic review. Credibility may be undermined by inappropriate eligibility criteria, inadequate literature search or failure to optimally summarize results. Second judgment: Rate the confidence in the effect estimates. Common reasons for lower confidence include high risk of bias of the individual studies, inconsistent results and small sample size. “Ultimately, clinicians have to ask if the results can directly apply to their patients,” Dr. Murad says.
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