Characteristics and knowledge synthesis approach for 456 network meta-analyses: a scoping review

Abstract

BackgroundNetwork meta-analysis (NMA) has become a popular method to compare more than two treatments. This scoping review aimed to explore the characteristics and methodological quality of knowledge synthesis approaches underlying the NMA process. We also aimed to assess the statistical methods applied using the Analysis subdomain of the ISPOR checklist.MethodsComprehensive literature searches were conducted in MEDLINE, PubMed, EMBASE, and Cochrane Database of Systematic Reviews from inception until April 14, 2015. References of relevant reviews were scanned. Eligible studies compared at least four different interventions from randomised controlled trials with an appropriate NMA approach. Two reviewers independently performed study selection and data abstraction of included articles. All discrepancies between reviewers were resolved by a third reviewer. Data analysis involved quantitative (frequencies) and qualitative (content analysis) methods. Quality was evaluated using the AMSTAR tool for the conduct of knowledge synthesis and the ISPOR tool for statistical analysis.ResultsAfter screening 3538 citations and 877 full-text papers, 456 NMAs were included. These were published between 1997 and 2015, with 95% published after 2006. Most were conducted in Europe (51%) or North America (31%), and approximately one-third reported public sources of funding. Overall, 84% searched two or more electronic databases, 62% searched for grey literature, 58% performed duplicate study selection and data abstraction (independently), and 62% assessed risk of bias. Seventy-eight (17%) NMAs relied on previously conducted systematic reviews to obtain studies for inclusion in their NMA. Based on the AMSTAR tool, almost half of the NMAs incorporated quality appraisal results to formulate conclusions, 36% assessed publication bias, and 16% reported the source of funding. Based on the ISPOR tool, half of the NMAs did not report if an assessment for consistency was conducted or whether they accounted for inconsistency when present. Only 13% reported heterogeneity assumptions for the random-effects model.ConclusionsThe knowledge synthesis methods and analytical process for NMAs are poorly reported and need improvement.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-016-0764-6) contains supplementary material, which is available to authorized users.

Comparative Effectiveness and Safety of Cognitive Enhancers for Treating Alzheimer's Disease: Systematic Review and Network Metaanalysis

“…Authors were contacted to obtain clarifications on study eligibility or provide data clarifications. AD severity was classified according to MMSE scores using the National Institute for Health and Care Excellence categories: mild (21-24), moderate (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), severe (<10). 22…”

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A systematic review of network meta-analyses for pharmacological treatment of common mental disorders

“…Compared with Chambers et al (2015), Zarin et al 26 and Petropoulou et al (2017) the NMAs included in this review more frequently provided a network diagram of both direct and indirect comparisons (70% compared with 61%, 48%, 26%, respectively); assessed consistency (75% compared with 69%, 53%, 30%, respectively) and made use of a random effects model (75% compared with 70%, 49%, 74%, respectively) 22 25 26. A higher proportion of NMAs in this review also modelled the data (75% vs 40% and 48%) and adjusted effect estimates for covariates (75% vs 29% and 18%), compared with Chambers et al 25 and Petropoulou et al (2017), respectively 22 25.…”

“…A higher proportion of NMAs in this review also modelled the data (75% vs 40% and 48%) and adjusted effect estimates for covariates (75% vs 29% and 18%), compared with Chambers et al 25 and Petropoulou et al (2017), respectively 22 25. The heterogeneity assumption was explored in 65% of the NMAs reported on in this paper, compared with 56% for Zarin et al 26 and Petropoulou et al (2017) 22 26. Finally, more than three quarters (77%) of the NMAs included in Petropoulou et al (2017) did not discuss transitivity, compared with 65% in our review 22…”

“…In addition, we modelled our approach on that of Chambers  et al 25 and the updated review by Zarin et al 26 and Petropoulou et al (2017) who assessed the following criteria: study method, study transparency and reproducibility, and the presentation of study findings22 25 26 (see online supplementary tables 2 and 3). …”