Mapping and systematic appraisal of umbrella reviews in biomedical literature: A protocol

Introduction: Umbrella reviews have emerged as a study design to deal with the increasing number of systematic reviews and meta-analyses. There is a rapid increase in the number of umbrella reviews being published, but there is no systematic assessment of their methodological and reporting characteristics. Our study will aim to fill this gap by performing a systematic mapping of umbrella reviews in biomedical literature. Methods We will perform a systematic review in PubMed to identify all the umbrella reviews that were published from inception until March 11, 2022. We will consider eligible any research article which was designated as an umbrella review in its title or abstract and summarizes systematic reviews and meta-analyses of any type of studies. From each eligible article, we will extract information about the research topic, the methodological characteristics, and the reporting characteristics. We will examine whether the umbrella reviews assessed the strength of the available evidence and the rigor of the included systematic reviews. We will also examine whether these characteristics change across time. Discussion Our study will systematically appraise the methodological and reporting characteristics of published umbrella reviews in biomedical literature. The findings of our study can be used to improve the design and conduct of future umbrella reviews, to derive a standardized set of reporting and methodological guidelines for umbrella reviews, and to allow further meta-epidemiological work. Systematic review registration: osf.io/sxzc6