How to write an umbrella review? A step-by-step tutorial with tips and tricks

The number of meta-analyses (MA) and systematic reviews (SR) on various medical issues has increased during the last two decades. The MA and SR results may differ from one another due to a number of factors such as inaccurate or diverse searches through the databases, discrepancies in the extraction process or in statistical analysis, among others. Some results may even contradict one another, resulting in confusion among readers. Umbrella reviews (UR) have allowed the collection of all available data on a medical issue into one concise study, making it the source of evidence-based medical knowledge to the highest degree. Furthermore, UR can resolve those problems by collecting all data and taking into account both MA and SR, making it the superior tool for physicians. Although the pros of UR are clear and the overall popularity of these types of study has increased tremendously, there is no available step-by-step guide on how to conduct one. Therefore, the objective of the present study was to provide researchers with a detailed tutorial on how to conduct an UR. UR represent the next major step in the advancement of evidence-based medicine, with great practical potential for physicians looking for the most up-to-date data on their topic of interest. We hope that our step-by-step guide may be a useful tool for researchers conducting UR in the future.