Efficacy of metformin versus lifestyle modifications in preventing type 2 diabetes mellitus: a meta-analysis of randomized controlled trials

Type 2 diabetes mellitus (T2DM) poses a growing global health burden. Prevention strategies typically focus on lifestyle modifications or pharmacological interventions, such as metformin, but their comparative efficacy remains unclear. This study aims to evaluate and compare the efficacy of metformin versus lifestyle modifications in reducing the incidence of T2DM among high-risk individuals. A comprehensive meta-analysis of randomized controlled trials (RCTs) was conducted. Systematic searches of PubMed, Embase, and Cochrane databases were performed. Eight RCTs involving 4,684 participants (2,324 in the metformin group and 2,360 in the lifestyle modification group) were included. The primary outcome was the incidence of T2DM, measured as odds ratio (OR) with corresponding 95% confidence intervals (CI). Heterogeneity was assessed using I² statistics. The pooled analysis demonstrated no significant difference in the incidence of T2DM between metformin and lifestyle modification groups (OR: 1.03, 95% CI: 0.64 to 1.65). Substantial heterogeneity was observed (I²=78%, p<0.0001). In conclusion, metformin and lifestyle modifications are similarly effective in preventing T2DM among high-risk individuals. These findings support the use of both interventions, with lifestyle modifications preferred for broader health benefits and metformin as a viable alternative for individuals unable to sustain lifestyle changes. Future studies should explore factors contributing to heterogeneity and assess long-term outcomes.