Insulin Resistance and Incident Heart Failure. The ARIC Study (Atherosclerosis Risk in Communities).

Objectives: This study was designed to assess the relationship between insulin resistance and incident heart failure (HF) in a community-based cohort. Background: Diabetes mellitus increases the risk for HF, but the association between insulin resistance and HF in individuals without diabetes is unclear. Methods: We prospectively analyzed 12,606 participants without diabetes mellitus, prevalent HF, or history of myocardial infarction at baseline (1987 to 1989) from the ARIC (Atherosclerosis Risk in Communities) study. We assessed the relationship between insulin resistance and incident HF using the homeostatic model assessment of insulin resistance (HOMA-IR) equation, adjusting for age, sex, race, body mass index, smoking, hypertension, center, and interim myocardial infarction. We tested for interactions by age, sex, obesity, and race. Results: Participants with insulin resistance, defined as HOMA-IR≥2.5 (n= 4,810, 39%), were older, more likely female, African American, hypertensive, and had a higher body mass index as compared with those without insulin resistance. There were 1,455 incident HF cases during a median of 20.6 years of follow-up. Insulin resistance defined by this threshold was not significantly associated with an increased risk for incident HF after adjustment (hazard ratio: 1.08, 95% confidence interval: 0.95 to 1.23). However, when analyzed continuously, this relationship was nonlinear, which indicated that risk increased, and was significantly associated with incident HF between HOMA-IR of 1.0 to 2.0, adjusting for baseline covariates; however, values over 2.5 were not associated with additional increased risk in adjusted models. Conclusions: In a community cohort, insulin resistance, defined by lower levels of HOMA-IR than previously considered, was associated with an increased risk for HF.