What is evidence-based medicine and the role of the systematic review: the revolution coming your way.

The practice of evidence-based medicine involves the critical application of current best evidence to the care of individual patients. This process requires clinicians to be able to efficiently locate, critically appraise and appropriately apply the best available evidence to particular clinical scenarios. The current volume of medical and scientific literature is unmanageable and traditional approaches to continuing education cannot fully address the information needs of practicing clinicians in the era of evidence-based medicine. Review articles are useful resources but traditional narrative reviews often include a selective summary of research findings mixed with personal opinion. Systematic reviews have many advantages over traditional narrative reviews; importantly, the use of systematic and explicit methods mean that bias in identifying, selecting and summarizing the evidence is minimized. For systematic reviews where meta-analysis can be performed, the quantitative synthesis of data from different studies can provide additional information. Systematic reviews are retrospective studies and like all research may be susceptible to bias. Furthermore some methodological issues related to meta-analysis have yet to be resolved. The strengths and limitations of systematic reviews are discussed in this article and useful resources for locating high quality systematic reviews are outlined. Clinical judgement and experience have a pivotal role in the practice of evidence-based medicine and clinicians must rely on this judgement when deciding how and when to apply the results of systematic reviews to particular patients.