Background Insulin beneficially affects myocardial functions during myocardial ischemia. It increases glucose-derived ATP production, decreases oxygen consumption, suppresses apoptosis of cardiomyocytes, and promotes the survival of cardiomyocytes. Patients with chronic heart failure generally have high insulin resistance, which is correlated with poor outcomes. The role of insulin in acute decompensated heart failure (ADHF) remains unclear. This study aimed to investigate the prognostic value of serum insulin level at the time of admission for long-term outcomes in patients with ADHF. Methods and Results We enrolled 1074 consecutive patients who were admitted to our department for ADHF. Of these 1074 patients, we studied the impact of insulin on the prognosis of ADHF in 241 patients without diabetes mellitus. The patients were divided into groups according to low, intermediate, and high tertiles of serum insulin levels. Primary end points were all-cause death and cardiovascular death. During a mean follow-up of 21.8 months, 71 all-cause deaths and 38 cardiovascular deaths occurred. Kaplan-Meier analysis showed that all-cause and cardiovascular mortality was significantly higher in the low-insulin group than those in the intermediate- and high-insulin groups (log-rank P=0.0046 and P=0.038, respectively). Moreover, according to the multivariable analysis, low serum insulin was an independent predictor of all-cause and cardiovascular mortality (hazard ratio, 2.37 [95% CI, 1.24-4.65; P=0.009] and 2.94 [95% CI, 1.12-8.19; P=0.028], respectively). Conclusions Low serum insulin levels were associated with increased risk of all-cause and cardiovascular death in ADHF patients without diabetes mellitus.
Keywords: acute heart failure; diabetes mellitus; insulin; prognosis.