Abstract
We aimed to evaluate the impact of diabetes mellitus (DM) and insulin treatment on clinical outcomes in patients with heart failure and preserved left ventricular ejection fraction enrolled in the TOPCAT study. We investigated the influence of DM status (insulin-treated [ITDM], non-insulin treated [NITDM], and no diabetes [non-DM]) at baseline on time to development of the primary end point, a composite of cardiovascular (CV) mortality, heart failure hospitalization, and aborted cardiac arrest. Secondary end points included the individual components of the primary end point, myocardial infarction, stroke, all-cause mortality, hyperkalemia, and worsened renal function. Due to marked regional differences in characteristics and outcomes of the TOPCAT patients, with much lower events in patients enrolled in Russia/Georgia, we restricted our analyses on findings from patients enrolled from the Americas. Compared to patients without DM, patients with ITDM had approximately 2-fold increased risk for the primary end point, heart failure hospitalization, and myocardial infarction (hazard ratios: 1.80, 1.97, and 2.27, respectively) and approximately 50% increases in all-cause and CV mortality. The risks for these outcomes were also increased in patients with ITDM in comparison to patients with NITDM as well (hazard ratios: 1.63, 1.65, and 2.73, respectively, and approximately 40% increases in all-cause and CV mortality). Patients with NITDM had similar risks for the primary end point and all secondary end points as patients without DM. In conclusion, the apparent increased risk of adverse outcomes in patients with heart failure and preserved left ventricular ejection fraction and ITDM merits future research to improve the prognosis of these high-risk patients.