Abstract
AIMS: Whereas homeostasis model assessment of insulin resistance (HOMA-IR), an easily measured but limited index of insulin resistance, has been shown to correlate with impairment of cardiac function in individuals without diabetes, the pathological relevance of insulin resistance to the development of cardiac dysfunction in individuals with type 2 diabetes has remained unclear. Here we investigated the relation between left ventricular (LV) function as assessed by echocardiography and insulin resistance as evaluated by hyperinsulinemic-euglycemic clamp analysis, the gold standard for measurement of this parameter, in individuals with type 2 diabetes. METHODS: This retrospective study included 34 individuals with type 2 diabetes who underwent both hyperinsulinemic-euglycemic clamp analysis and echocardiography. Both the insulin sensitivity index (ISI) as determined by glucose clamp analysis as well as HOMA-IR were determined as measures of insulin resistance. The ratio of the peak early- to late-diastolic mitral inflow velocities (E/A) and the LV ejection fraction (LVEF) were determined as measures of diastolic and systolic function, respectively. RESULTS: The ISI was significantly correlated with both the E/A ratio and LVEF (correlation coefficients of 0.480 and 0.360, respectively), whereas HOMA-IR was not correlated with either cardiac parameter. Multivariate analysis revealed that ISI was an independent predictor for both a high log [E/A] (P = 0.031) and a high LVEF (P = 0.045). CONCLUSIONS: Insulin resistance as evaluated by hyperinsulinemic-euglycemic clamp analysis may be causally related to LV diastolic and systolic dysfunction in individuals with type 2 diabetes.