The impact of metformin on mortality in patients with type 2 diabetes mellitus: a prospective cohort study

Metformin, a widely used antihyperglycemic drug, has shown efficacy in treating type 2 diabetes mellitus (T2DM) and is associated with potential benefits beyond glycemic control. This study investigates the impact of metformin on mortality in T2DM patients using a prospective cohort design utilizing data from the National Health and Nutrition Examination Survey (NHANES).

In NHANES 1999–2014, a total of 5813 representative participants aged 20 and above with T2DM were included in the analysis. We utilized Kaplan–Meier survival curves and multivariate Cox regression analysis to investigate the impact of metformin on both all-cause mortality and cause-specific mortality among patients with T2DM.

Kaplan–Meier analysis showed a significant reduction in all-cause and cause-specific mortality in metformin users compared to non-users (p < 0.05). Multivariate Cox regression confirmed these findings, indicating that metformin use was associated with a 18% reduction in all-cause mortality (HR = 0.82, 95% CI = 0.73–0.92, p < 0.001) and 25% reduction in cardiovascular mortality (HR = 0.75, 95% CI = 0.60–0.94, p = 0.01).

Our results suggest that metformin significantly reduces all-cause and cardiovascular mortality in T2DM patients, highlighting its potential benefits beyond glycemic control. These results contribute to the existing literature by providing robust evidence from a large prospective cohort study. However, further research is needed to validate these findings and elucidate the underlying mechanisms controlling the effects of metformin on mortality outcomes in individuals with T2DM.