Comparison of carotid intima-media thickness, arterial stiffness, and brachial artery flow mediated dilatation in diabetic and nondiabetic subjects (The Chennai Urban Population Study [CUPS-9])

Abstract

This study compares flow-mediated dilation (FMD) and the augmentation index (AI) in diabetic and nondiabetic subjects and correlates these measurements with carotid intima-media thickness (IMT). Fifty diabetic subjects and 50 age- and sex-matched nondiabetic control subjects were recruited from the Chennai Urban Population Study. IMT of the common carotid artery and FMD of the brachial artery were determined using high-resolution B-mode ultrasonography. AI was measured using the Sphygmocor apparatus. The mean AI of diabetic subjects was significantly higher than the nondiabetic subjects (27.48 ± 7.41% vs 19.10 ± 8.19%, p <0.0001). The FMD values were significantly lower among diabetic subjects compared with the nondiabetic subjects (2.1 ± 2.95% vs 6.64 ± 4.38%, p < 0.0001). At any given age point, diabetic subjects had significantly higher AI and lower FMD values compared with nondiabetic subjects (p <0.05). In the total population, AI and FMD showed a correlation with age (p <0.001), fasting plasma glucose (p <0.01), glycosylated hemoglobin (p = 0.001), and IMT (p = 0.001). Among the nondiabetic subjects, FMD and AI showed a strong correlation with IMT. FMD also showed a strong correlation with age and systolic blood pressure, whereas AI showed a correlation with fasting plasma glucose in diabetic subjects. AI and FMD values showed a strong correlation with age. AI values increased and FMD values decreased with an increase in quartiles of IMT both in diabetic and nondiabetic subjects. Multivariate linear regression analyses in the total study population showed that age and glycosylated hemoglobin were the risk factors associated with AI and FMD, in addition to diastolic blood pressure with AI. Diabetic patients have decreased FMD and increased arterial stiffness compared with age- and sex-matched nondiabetic subjects. These functional changes correlate well with the structural changes of the arteries measured by IMT.