Observational study of the efficacy of prolonged-release metformin in people with prediabetes

Objectives: Prediabetes is characterized by elevation of indices of blood glucose that is insufficient to provoke a diagnosis of type 2 diabetes, but markedly increases the risk of developing type 2 diabetes in the future. Lifestyle interventions are the main therapeutic intervention for the management of prediabetes. Current guidelines also support treatment of prediabetes with metformin for selected subgroups of patients, and metformin has a therapeutic indication for this use in a number of countries.Methods: We performed an observational, non-interventional study of the effects on glycaemia of prolonged-release metformin (Glucophage XR, referred to henceforth as metformin XR) in 686 subjects with prediabetes. Metformin was prescribed according to physicians’ usual care practices, and the study duration was 12 weeks.Results: Mean (SD) fasting plasma glucose (FPG) at baseline was 6.2 (0.4) mmol/L [111 (8) mg/dL) and was reduced by –0.55 (0.7) mmol/L [–10 (13) mg/dL] after 12 weeks of metformin XR. FPG was normalized to below the American Diabetes Association cut-off for the diagnosis of prediabetes (<5.7 mmol/L [100 mg/dL]) in 43% of subjects. Increasing age, increasing body mass index, not following a weight-loss diet and alcohol use predicted a lower probability of normalized FPG. Metformin was well tolerated, with most side effects occurring in the gastrointestinal system, as expected.Conclusions: Metformin XR normalized FPG in about two-fifths of subjects with prediabetes. These real-world data add further support a role for metformin in the management of prediabetes, in line with current guidelines in this area.