Systematic reviews and meta-analyses: an illustrated, step-by-step guide.

Systematic reviews and meta-analyses synthesize data from existing primary research, and well-conducted reviews offer clinicians a practical solution to the problem of staying current in their fields of interest. A whole generation of secondary journals, pre-appraised evidence libraries and periodically updated electronic texts are now available to clinicians. However, not all systematic reviews are of high quality, and it is important to be able to critically assess their validity and applicability. This article is an illustrated guide for conducting systematic reviews. A clear understanding of the process will provide clinicians with the tools to judiciously appraise reviews and interpret them. We hope that it will enable clinicians to conduct systematic reviews, generate high-quality evidence, and contribute to the evidence-based medicine movement.