Risk of Bias in Network Meta-Analysis (RoB NMA) tool

Abstract

Systematic reviews with network meta-analysis (NMA) have potential biases in their conduct, analysis, and interpretation. If the results or conclusions of an NMA are integrated into policy or practice without any consideration of risks of bias, decisions could unknowingly be based on incorrect results, which could translate to poor patient outcomes. The RoB NMA (Risk of Bias in Network Meta-Analysis) tool answers a clearly defined need for a rigorously developed tool to assess risk of bias in NMAs of healthcare interventions. In this guidance article, we describe and provide a justification for the tool’s 17 items, their mechanism of bias, pertinent examples, and how to assess an NMA based on each response option. A network meta-analysis (NMA) is a type of quantitative analysis that can be performed as part of a systematic review.1234 An NMA is an extension of a pairwise meta-analysis that compares the effects of multiple interventions simultaneously on one clinical, public health, or policy question.1 NMAs provide coherent estimates of comparative effectiveness for all pairs of interventions in the network, including interventions that have never been previously compared in a head-to-head study. Furthermore, NMAs allow for the ranking of all interventions in a network of studies.5 Systematic reviews with NMA have potential biases in their conduct, analysis, and interpretation.67 Quality assessment of the evidence is integral to the practice of evidence based medicine. If the results or conclusions of an NMA are integrated into policy or practice without any consideration of the risks of bias, decisions could unknowingly be based on incorrect results, with the potential for these to translate to poor patient outcomes. Therefore, NMAs should be assessed in terms of potential for bias. The Risk of Bias in Network Meta-Analysis (RoB NMA) tool was developed because no …