This was a meta-analysis that aimed to compare the effectiveness of metformin to lifestyle interventions in preventing diabetes in individuals with prediabetes. 5 studies met this meta-analysis’ eligibility criteria. Across these 5 studies, sample sizes ranged from 57 to 2052, and the mean age of patients ranged from 45 to 64. All studies were randomized controlled trials that compared a metformin group to a lifestyle modification group. Across the studies, metformin dosages were either 250 mg 2 times a day or 3 times a day, or 850 mg twice a day. The lifestyle modification programs included individual and group counseling sessions, lifestyle coaching, and dietary teaching with physical exercise. Sessions were held either weekly, monthly, or bi-annually. Patients were followed up on between 1 and 3 years later. The main results of the meta-analysis were: 1) there was no significant difference in the risk of developing diabetes between the metformin and lifestyle intervention groups; 2) the risk of diabetes was slightly higher in the metformin group, but this difference was not statistically significant; 3) when comparing metformin and lifestyle intervention to lifestyle intervention alone, no significant difference was observed in the incidence of diabetes. They also did address the limitations of their research, which included their small number of studies and that they did not evaluate adherence to lifestyle interventions. Ultimately, the authors concluded that the combination of lifestyle interventions and metformin is more effective in reducing the risk of diabetes and has a synergistic effect. Their conclusion is corroborated by the finding that lifestyle interventions can be designed to directly address two key risk factors (obesity, reduced physical activity) and that the effects of pharmacologic intervention diminish after discontinuation.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10646693/pdf/cureus-0015-00000047105.pdf