INCREASED CAROTID INTIMA-MEDIA THICKNESS IN HYPERURICEMIC INDIVIDUALS MAY BE EXPLAINED BY HYPERHOMOCYSTEINEMIA ASSOCIATED WITH RENAL DYSFUNCTION

Abstract

Background Both hyperuricemia and hyperhomocysteinemia are known to be associated with the deterioration of vascular endothelial function and are regarded as important risk factors for atherosclerotic vascular diseases. However, there has been no report about the relationship between homocysteine (Hcy) and atherosclerosis in patients with hyperuricemia.

Objectives In this study, we evaluated the relationship between the carotid IMT and various clinical parameters including renal function and serum Hcy level in patients with hyperuricemia, and investigated the possible mechanism of how hyperuricemia is related with the increase of carotid IMT.

Methods A total of 1228 subjects who visited the health promotion centre of hospital were enrolled in this study. All subjects completed both carotid ultrasonography and laboratory measurement, including serum Hcy levels and renal function. Serum Hcy levels were measured by a competitive immunoassay using direct chemiluminescent. Carotid IMT was evaluated by B-mode carotid ultrasonography.

Results Hyperuricemic patients showed higher carotid IMT values compared with normouricemic patients (1.12±0.64 mm vs. 1.02±0.50 mm, p=0.043). The serum Hcy levels were significantly higher in the hyperuricemic group than in the normouricemic group (13.39±4.42 μmol/L vs. 11.69±3.65 μmol/L, p<0.001). In patients with hyperuricemia, serum uric acid levels were negatively correlated with estimated glomerular filtration rates (eGFR) (γ=−0.334, p<0.001), and eGFR were negatively correlated with serum Hcy levels (; γ=−0.490, p<0.001). Carotid IMT was correlated with serum Hcy levels (γ=0.196, p=0.008), and atherosclerotic changes of carotid artery measured by carotid ultrasonography increased 1.09-fold (OR, 95% CI 1.006–1.185, p=0.036) per 1 μmol/L difference in serum homocysteine levels. In multivariate linear regression analysis, carotid IMT was affected by reduced eGFR (β=−0.263, p=0.002).

Conclusions Carotid IMT was higher in patients with hyperuricemia than in normouricemic individuals. This study suggests that impairment of the renal function in patients with hyperuricemia may induce the increase in carotid IMT via increased serum Hcy levels.