Metformin and risk of long-term mortality following an admission for acute heart failure

Aims Optimal diabetic treatment in patients with established heart failure remains unclear. Metformin has been traditionally considered well tolerated in patients with cardiovascular disease, although there is scarce information regarding the prognostic implications of metformin in acute heart failure. We sought to evaluate the association between metformin therapy and risk of long-term mortality in patients discharged for decompensated heart failure. Methods We included 835 consecutive type 2 diabetic patients discharged from a cardiology department of a third-level center. All-cause mortality was considered as the primary endpoint and the effect of metformin therapy across the most representative subgroups in heart failure as a secondary endpoint. The association between metformin with all-cause mortality was evaluated by using a Cox regression method. Multivariate analysis included solid prognostic covariates in heart failure. ResultsAt a mean follow-up of 2.42 years, mortality rates were significantly lower in patients on treatment with metformin: 1.34 (1.04-1.65)x10 vs. 2.24 (2.0-2.51)x10 person-years (P<0.001). Kaplan-Meier curve revealed a progressive separation of curves already observed during first months of follow-up (log-rank test P<0.001). In multivariate analysis, this prognostic association remained significant. Conclusion In this cohort of patients with acute heart failure and diabetes, metformin appears to be well tolerated and may be associated with favorable clinical outcomes.