Subclinical atherosclerosis is increased in type 2 diabetic patients with microalbuminuria evaluated by intima-media thickness and pulse wave velocity

BACKGROUND: Microalbuminuria appears to be a risk marker for atherosclerosis. However, little is known about the direct association between microalbuminuria and vascular wall properties. METHODS: Subjects were 306 type 2 diabetic patients with normoalbuminuria (N= 200) and microalbuminuria (N= 106). Those who had macroalbuminuria, atherosclerotic vascular disease, and/or ankle brachial index being less than 0.9 were not included. Brachial-ankle pulse wave velocity (PWV) was measured by automatic oscillometric method. Intima-media thickness (IMT) of the common carotid artery was measured using high-resolution B-mode ultrasonography and a computerized image-analyzing system. RESULTS: Average IMT, maximum IMT, and PWV were significantly higher in patients with microalbuminuria than in patients with normoalbuminuria. Both average and maximum IMT increased significantly as albuminuria increased in the microalbuminuric range. Average IMT and maximum IMT correlated significantly with PWV (P < 0.0001), although some patients exhibited increased levels of only PWV or IMT. By a multiple linear regression, age and albuminuria were independent predictors of IMT and PWV. Waist circumference was an independent predictor of IMT. Hypertension and hemoglobin A(1c) (HbA(1c)) were independent predictors of PWV. After adjustment for conventional cardiovascular risk factors including age, sex, waist circumference, HbA(1c), hypertension, hyperlipidemia, and smoking, albuminuria revealed a significant association with average IMT, maximum IMT, and PWV (P < 0.05, P < 0.0001, and P < 0.05, respectively). CONCLUSION: A slight elevation of albuminuria is a significant determinant of IMT and PWV independent of conventional cardiovascular risk factors in type 2 diabetic patients with no clinical nephropathy or any vascular diseases. This significant association might point to a link in the pathogenesis of atherosclerosis and diabetic nephropathy.