Network meta-analysis (NMA) is an extension of pairwise meta-analysis that facilitates comparisons of multiple interventions over a single analysis. It is the method in which multiple interventions (that is, three or more) are compared using both direct comparisons of interventions within randomized controlled trials and indirect comparisons across trials based on a common comparator. NMA is methodologically complex compared to simple pairwise meta-analysis as it accounts for a broader evidence base. Results from NMA are more useful to policy makers, service commissioners, and providers when making choices between multiple alternatives than those from multiple, separate pairwise meta-analyses. It can be an ideal choice to be extended to compare complex interventions that are multifaceted. Apart from the numerous benefits the NMA offers, it is prone to methodological complications that need to be understood, implemented, and finally reported correctly. This article is meant to provide a primer to the various methodological issues pertaining to NMA. The NMA can be as valid as a standard pairwise meta-analysis if these methodological issues are taken care of.
Key words: Network meta-analysis, indirect comparison, multiple treatment comparison, mixed treatment comparison.
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