Association between Homa Index and Vascular Endothelial Dysfunction in Type 2 Diabetic Patients

Abstract

Introduction: In recent years, flow mediated dilatation (FMD) has become a popular technique in cardiovascular medicine. HOMA-IR was accepted to determine the insulin sensitivity as a valuable standard. In this study, we evaluated the association between HOMA-IR (homeostasis model assessment of insulin resistance) and vascular endothelial dysfunction, as assessed by endothelium- dependent flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD), in type 2 Diabetic (DM) patients. Material and Methods: Eighty four (84) consecutive out-patients were enrolled. HOMA-IR was calculated as fasting insulin (μU/ml) multiplied by fasting plasma glucose (FPG) (mg/dl) and divided by 405. The ultrasound method for measuring FMD and NMD has been used. Out of 84 patients, 42 patients were in control group and 42 patients were in diabetic group, which were further subdivided into two groups based on HOMA-IR > 3.0 and above was considered as Group I and HOMA IR < 3.0 and below was considered as Group II. Fasting Plasma Glucose (mmol/dl) (7.74 ± 2.56, 6.81 ± 1.9, p < 0.001) and Fasting Insulin (μU/dl) (13.26 ± 8.09, 6.65 ± 2.36, p < 0.001) were statistically significant in Group I. The baseline mean FMD in controls and cases (Group I and Group II) was 15.36 ± 9.56, 4.15 ± 2.29, 12.21 ± 6.24 (p < 0.001) respectively. By logistic regression analysis the factors which were effective on FMD percentage change (<5.5%) in Group I were BMI (p < 0.02), plasma Insulin (p < 0.04) and triglycerides (p < 0.02). There was a negative co-relation for FMD, NMD and HOMA-IR. Discussion: We conclude that increased HOMA-IR in hyperglycaemic patients is associated with severe endothelial dysfunction which is the marker of the atherosclerosis. Thus the measurement of endothelial vasomotor function which is a comprehensive analysis of atherosclerotic burden may provide a better predictive value of future cardiovascular events than the analysis of each of the traditional risk factors alone.