A Simple Guide to Systematic Reviews and Meta-Analyses.

Systematic reviews and meta-analyses lie on the top of the evidence hierarchy because they utilize explicit methods for literature search and retrieval of studies relevant to the review question as well as robust methodology for quality assessment of included studies and quantitative synthesis of results. As opposed to narrative reviews which represent the authors' personal judgments, they may be more resource-intensive, but provide an unbiased answer to a specific clinical query. Clinical guidelines are usually supported by such evidence syntheses. Therefore, it is important that healthcare practitioners become competent in understanding and applying systematic review findings. This simple guide outlines the key principles regarding the design, conduct and interpretation of systematic reviews and meta-analyses.