Objective: Carotid intima-media thickness (C-IMT) measured noninvasively by ultrasonography is now widely used as a surrogate marker for atherosclerotic disease and directly associated with increased risk of cardiovascular disease. Hyperuricemia (HU) is a well recognized risk factor for cardiovascular diseases. The independence of this association from other confounding factors has remained controversial. But the possible contributory effect of HU to carotid intima-media thickness (C-IMT) produced by hypertension (HT) has not been clarified yet. The study was designed to assess the C-IMT in patients with hypertension (HT) with or without HU.
Methods: The study participants consisted of 30 patients (men 60%, mean age+/-S.D.: 49+/-11 years) with HT without HU, and 25 patients with HT and HU (men 52%, mean age+/-S.D.: 52+/-12 years), and 25 age-matched healthy control subjects (men 56%, mean age+/-S.D.: 50+/-13 years). All study groups were examined by B-mode ultrasound to measure the C-IMT at the far wall of the common carotid artery.
Results: C-IMT were significantly higher in the patient groups (HT without HU and HT with HU) compared to the control cases (0.70+/-0.14, 0.83+/-0.16 versus 0.57+/-0.16, mm, respectively, p<0.001). In the patients groups, patients with HU had significantly higher carotid IMT compared to the patients without HU. In stepwise linear regression analysis, we found that serum uric acid (SUA) levels independently but modestly associated with C-IMT (beta=0.42, p=0.002).
Conclusion: We have shown that higher SUA levels are associated with atherogenesis independent from hypertension. Prospective studies will be necessary to confirm and extend these findings including early screening for hyperuricemia and lowering of SUA level looking at potential benefits in slowing progression of C-IMT in hypertensive patients.