Methodological improvements are needed in network meta-analyses of antidiabetic drugs for type 2 diabetes mellitus: a systematic review

Anna Dai^1,2Yang Liu^1,2Jiali Yin^1,2Qianqian Wang^1,2Maoyi Yang²Xiaoli Ji^2*Zhipeng Hu^2*

• ¹Chengdu University of Traditional Chinese Medicine, Chengdu, China
• ²Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China

Introduction: Numerous network meta-analyses have compared the efficacy of antidiabetic drugs for type 2 diabetes mellitus. However, a systematic assessment of their methodological and reporting quality remains lacking. Methods: We searched the PubMed, Embase, and Cochrane Library databases for relevant studies from inception to July 21, 2025 for published network meta-analyses that compares the efficacy of antidiabetic drugs for type 2 diabetes mellitus. The methodological and reporting quality of included studies was assessed by the Assessment of Multiple Systematic Reviews 2 checklist and the PRISMA-NMA checklist. Regression analyses were performed to identify factors potentially associated with the methodological quality of the included studies. Results: A total of 185 NMAs were included. Over half of the studies (58.38%) originated from developing countries. Most studies focused on comparison of multiple antidiabetic drugs (122, 65.95%), and the majority used Bayesian methods (98, 52.97%). The overall methodological quality was low, with only one study rated as high quality. Critical items of AMSTAR 2 were poorly reported, with only 2.70% of studies adequately reporting item 7 and 58.38% reporting item 2. Significant associations were observed between study quality and analytical framework, outcome, economic development level, journal impact factor, and protocol registration status. Conclusion: Network meta-analyses that compares antidiabetic drugs for T2DM exhibit substantial methodological limitations and advancements in methodology are critically needed in future research.