Low Insulin Sensitivity Measured by Both Quantitative Insulin Sensitivity Check Index and Homeostasis Model Assessment Method as a Risk Factor of Increased Intima-Media Thickness of the Carotid Artery

The present study evaluated the association of ultrasonographic manifestations of carotid atherosclerosis with glucose status, various components of the insulin resistance syndrome, and insulin sensitivity measured by a novel quantitative insulin sensitivity check index (QUICKI = 1/[log(I0) + log (G0)]). Carotid ultrasonographic measurements were performed on 54 diabetic subjects, 97 subjects with impaired glucose tolerance and 57 normoglycemic subjects. QUICKI and insulin resistance measured by a HOMA (homeostasis model assessment) method had a high negative correlation (r = -0.995, P < 0.001). QUICKI was lower in diabetic subjects (0.319 +/- 0.022) than in subjects with impaired glucose tolerance (0.334 +/- 0.027) or normoglycemia (0.335 +/- 0.022, P = 0.002). There was an increasing trend in the mean and maximal intima-media thickness (IMT) of the common carotid artery (CCA) with worsening of glucose status. The maximal IMT of the CCA correlated inversely with QUICKI (r = -0.158, P = 0.027). The prevalence of severe CCA atherosclerosis (maximal IMT of the CCA > or = 1.2 mm) was 41% in men and 16% in women (P < 0.001). It was also associated with a long (> or =26 yr) smoking history. The prevalence of severe CCA atherosclerosis was 11% in the highest QUICKI tertile, 36% in the middle tertile, and 33% in the lowest tertile (P = 0.002). Systolic blood pressure was higher and high-density lipoprotein cholesterol lower in subjects with severe CCA atherosclerosis, compared with those without it. In multiple regression analysis, the adjusted odds ratio for severe CCA atherosclerosis was 5.7 (95% confidence interval, 2.2-15.1) in subjects in the two lowest tertiles of QUICKI, compared with those in the highest tertile.