Methodological Approaches for Assessing Certainty of the Evidence in Umbrella Reviews: a Systematic Review
Abstract Objective: To identify and describe the methodological approaches for assessing the certainty of the evidence in umbrella reviews (URs) of meta-analyses (MAs).Study Design and Setting: We included URs that included SR-MAs of interventions and non-interventions. We searched from 3 databases including PubMed, Embase, and The Cochrane Library from 2010 to 2020.Results: 138 URs have been included consisting of 96 and 42 URs of interventions and non-interventions, respectively. Only 31 (32.3%) of URs of interventions assessed certainty of evidence, in which the GRADE approach was the most frequently used method (N=20, 64.5%) followed by creditability assessments (N=6, 12.9%). Conversely, thirty (71.4%) of URs of non-interventions assessed certainty of evidence, in which the criteria for credibility assessment were mainly used (N=28; 93%). URs published in journals with high journal impact factor (JIF) are more likely to assess certainty of evidence than URs published in low JIFs. Conclusions: Only one-third of URs that included MAs of experimental designs have assessed the certainty of the evidence in contrast to the majority of the URs of observational studies. Therefore, guidance and standards are required to ensure the methodological rigor and consistency of certainty of evidence assessment for URs.