Background
Patients with heart failure (HF) have higher fasting insulin levels and a higher prevalence of insulin resistance (IR) as compared with matched controls. IR leads to structural abnormalities in the heart, such as increased left atrial (LA) size, left ventricular (LV) mass, and alterations in transmitral velocity that can precede the diagnosis of HF. It is not known whether IR precedes the development of HF or whether the relationship between IR and HF is present among adults with HF due to non-ischemic heart disease.
Methods and Results
We examined 4425 participants (60% female) from the Cardiovascular Health Study after excluding those with HF, myocardial infarction, or treated diabetes at baseline. We used Cox proportional hazards models to estimate the relative risk of incident HF associated with fasting insulin measured at study entry.
There were 1216 cases of incident HF (1103 without antecedent MI) during a median follow-up of 12 years (maximum, 19 years). Fasting insulin levels were positively associated with the risk of incident HF (HR = 1.10, 95% CI 1.05, 1.15, per SD change) when adjusted for age, gender, race, field center, physical activity, smoking, alcohol intake, HDL cholesterol, total cholesterol, and systolic blood pressure, and waist circumference. The association between fasting insulin levels and incident HF was similar for HF without antecedent MI (HR= 1.10, 95% CI 1.05, 1.15). Measures of LA size, LV mass, and peak A velocity at baseline were associated both with fasting insulin levels and with heart failure ; however, additional statistical adjustment for these parameters did not completely attenuate the insulin-HF estimate (HR= 1.08, 95% CI 1.03, 1.14 per1-SD increase in fasting insulin).
Conclusion
Fasting insulin was positively associated with adverse echocardiographic features and risk of subsequent HF in CHS participants, including those without an antecedent MI.
