3381Treatment with insulin is associated with worse outcome in patients with chronic heart failure and diabetes

Introduction: Up to a third of patients with type II diabetes mellitus and heart failure are treated with insulin. Hypothesis: The safety of insulin in patients with heart failure and type II diabetes mellitus is unknown. It can cause sodium retention and hypoglicemia, so it might worse prognosis of heart failure patients. Methods: We examined two datasets: (1) 24,012 patients with heart failure from 4 large randomized trials and (2) an administrative database of 4 million individuals. In the former, survival was examined using Cox proportional hazards models adjusted for baseline variables and separately for propensity scores. Fine-Gray competing risk regression models were used to assess the risk of hospitalization for heart failure. For the latter a case-control study nested within a population-based cohort study was conducted with propensity score. Results: Prevalence of diabetes at study entry ranged from 25.5% to 29.5% across trials. Insulin alone or in combination with oral hypoglycemic drugs was prescribed at randomization to 24.4% to 34.5% of the patients with diabetes. Age was similar for patients with and without diabetes and for patients with diabetes, irrespective of whether they received insulin. The rates of death from any cause and hospitalization for heart failure were higher in patients with diabetes vs no-diabetes, and highest of all in patients prescribed insulin (propensity score pooled HR for all-cause mortality 1.27 [1.16–1.38], for heart failure hospitalization 1.23 [1.13–1.33]). In the administrative registry, insulin prescription was associated with a higher risk of all-cause death (OR 2.02 95% CI [1.87–2.19]) and re-hospitalization for heart failure (OR 1.42 95% CI [1.32–1.53]).