Umbrella Reviews: What They Are and Why We Need Them

Evidence in clinical research is accumulating and scientific publications have increased exponentially in the last decade across all disciplines. Available information should be critically assessed. Here, we focus on umbrella reviews, an approach that systematically collects and evaluates information from multiple systematic reviews and meta-analyses. To facilitate the design and the conduct of such a study, we provide a step-by-step guide on how to perform an umbrella review. We also present ways to report the summary findings, we describe various proposed grading criteria, and we discuss potential limitations.