Insulin-treated diabetes is associated with a marked increase in mortality in patients with advanced heart failure

Objectives This study aimed to investigate the effect of diabetes and insulin use on survival in a large cohort of patients with advanced heart failure (HF) of multiple etiologies. Background Although diabetes is a well-known risk factor for both systolic and diastolic dysfunction, the impact of diabetes and insulin treatment on prognosis of patients with HF has not been well studied. Methods History of diabetes and insulin treatment was assessed in 554 consecutive patients with advanced systolic HF who presented to a single center for HF management and/or transplant evaluation (mean age 52.0 ± 13.1 years, ejection fraction 24.6 ± 7.4). Patients were stratified into 3 groups based on presence or absence of diabetes and insulin use. Differences in patient characteristics and survival were evaluated. Results There were 132 patients (23.8%) with diabetes; 43 patients (7.8%) were insulin treated and 89 patients (16.1%) were non–insulin-treated patients with diabetes. The groups were similar in sex, smoking history, medication profile, ejection fraction, body mass index, and serum sodium. Survival at 1 year was 89.7% for nondiabetic patients, 85.8% for non–insulin-treated diabetic patients, and 62.1% for insulin-treated diabetic patients (P < .000 01). After Cox multivariate analysis, insulin-treated diabetes was found to be an independent predictor of mortality (hazard ratio 4.30, 95% CI 1.69-10.94) whereas non–insulin-treated diabetes was not (hazard ratio 0.95, 95% CI 0.31-2.93). Similar findings were seen in clinically relevant subgroups. Conclusions Insulin-treated diabetes is associated with a significantly worse prognosis in patients with advanced HF. Further investigations into mechanisms for the association of insulin treatment and mortality in patients with HF are warranted.