Umbrella Review Methodology

An umbrella review consolidates evidence across reviews when the evidence base is fragmented or methodologically inconsistent. Overlap of primary studies across included reviews will be assessed with Corrected Covered Area to avoid duplicate counting. Methodological quality will be assessed with AMSTAR 2 by two or more independent reviewers. Methodological quality of included reviews will be assessed using AMSTAR-2 by two independent blinded scientists. The review protocol has been registered in PROSPERO. The protocol was developed using Joanna Briggs Institute guidance for umbrella reviews and a methodological guide for umbrella reviews. Umbrella reviews are considered suitable for broad evidence bases because they can assess consistency, contradiction, and context dependence across reviews.