Associations of dipeptidyl peptidase‐4 inhibitors with mortality in hospitalized heart failure patients with diabetes mellitus

BACKGROUND: Heart failure (HF) and diabetes mellitus (DM) often co‐exist. Treatment of DM in HF patients is challenging because some therapies for DM are contraindicated in HF. Although previous experimental studies have reported that dipeptidyl peptidase‐4 (DPP‐4) inhibitors improve cardiovascular function, whether DPP‐4 inhibition improves mortality of HF patients with DM remains unclear. Therefore, we examined the impact of DPP‐4 inhibition on mortality in hospitalized HF patients using propensity score analyses. METHODS AND RESULTS: We performed observational study analysed by propensity score method with 962 hospitalized HF patients. Of these patients, 293 (30.5%) had DM, and 122 of these DM patients were treated with DPP‐4 inhibitors. Propensity scores for treatment with DPP‐4 inhibitors were estimated for each patient by logistic regression with clinically relevant baseline variables. The propensity‐matched 1:1 cohorts were assessed based on propensity scores (DPP‐4 inhibitors, n = 83, and non‐DPP‐4 inhibitors, n = 83). Kaplan–Meier analysis in the propensity score‐matched cohort demonstrated that cardiac and all‐cause mortality was significantly lower in the DPP‐4 inhibitor group than in the non‐DPP‐4 inhibitor group (cardiac mortality: 4.8% vs. 18.1%, P = 0.015; all‐cause mortality: 14.5% vs. 41.0%, P = 0.003, by a log‐rank test). In the multivariable Cox proportional hazard analyses, after adjusting for other potential confounding factors, the use of DPP‐4 inhibitors was an independent predictor of all‐cause mortality (pre‐matched cohort: hazard ratio 0.467, P = 0.010; post‐matched cohort: hazard ratio 0.370, P = 0.003) in HF patients with DM. CONCLUSIONS: Our data suggest that DPP‐4 inhibitors may improve cardiac and all‐cause mortality in hospitalized HF patients with DM.