A GRADE Working Group approach for rating the quality of treatment effect estimates from network meta-analysis

Abstract

Network meta-analysis (NMA), combining direct and indirect comparisons, is increasingly being used to examine the comparative effectiveness of medical interventions. Minimal guidance exists on how to rate the quality of evidence supporting treatment effect estimates obtained from NMA. We present a four-step approach to rate the quality of evidence in each of the direct, indirect, and NMA estimates based on methods developed by the GRADE working group. Using an example of a published NMA, we show that the quality of evidence supporting NMA estimates varies from high to very low across comparisons, and that quality ratings given to a whole network are uninformative and likely to mislead. Network meta-analysis (NMA) that simultaneously addresses the comparative effectiveness and/or safety of multiple interventions through combining direct and indirect estimates of effect is rapidly gaining popularity and influence.1 2 3 4 5 6 Although NMA approaches appear attractive,6 7 8 application of their results requires understanding the quality of the evidence. By quality of evidence, we mean the degree of confidence or certainty one can place in estimates of treatment effects. NMA is sufficiently new that terminology differs between authors and continues to evolve. Box 1 presents a glossary of terms used in this article. #### Box 1: Glossary of terms (in order they appear in the text)