Insulin Resistance Is Highly Prevalent and Is Associated With Reduced Exercise Tolerance in Nondiabetic Patients With Heart Failure

Objectives: The purpose of this study was to establish the prevalence of insulin resistance (IR) among nondiabetic chronic heart failure (CHF) patients and to seek factors associated with IR in CHF, including the relationship of IR to functional class, exercise capacity, and disease severity in CHF. Background Several lines of evidence suggest that CHF is an IR state. The prevalence of IR in CHF and its relation to CHF have not been fully defined. Methods Fasting insulin resistance index (FIRI) was assessed in a cohort of 129 consecutive CHF patients (mean age 69.2 +/- 10.4 years; 76% males; body mass index 27.4 +/- 4.4 kg/m(2)). Patients underwent cardiopulmonary exercise testing and peripheral endothelial function testing by reactive hyperemia peripheral arterial tonometry (RH-PAT). Results: Prevalence of IR as defined by FIRI greater than or equal to 2.7 was 61% in our cohort of CHF patients. There was a significant correlation between IR and waist circumference (r = 0.37; p less than 0.01), serum triglycerides (r = 0.34; p less than 0.01), high-density lipoprotein cholesterol (r = -0.22; p = 0.02), and serum leptin (r = 0.39; p = 0.03). Insulin resistance increased significantly with worsening New York Heart Association functional class (p less than 0.01). The CHF patients with IR had a significantly lower exercise capacity and peak oxygen consumption than patients with an FIRI less than 2.7. The RH-PAT ratio was significantly lower in CHF patients with IR compared with CHF patients with an FIRI less than 2.7 (1.6 +/- 0.3 vs. 2.0 +/- 0.5; p less than 0.05). Conclusions: Insulin resistance is highly prevalent among nondiabetic CHF patients and is associated with decreased exercise capacity in patients with CHF