Increased Carotid Intima-Media Thickness (IMT) in Hyperuricemic Individuals May Be Explained by Hyperhomocysteinemia Associated with Renal Dysfunction: a Cross-Sectional Study

BACKGROUND: Both hyperuricemia and hyperhomocysteinemia are known as main risk factors of cardiovascular diseases. There has been, however, no report on the relationship between carotid intima-media thickness (IMT) and homocysteine (Hcy) in hyperuricemic patients. This study aimed to investigate how hyperuricemia is associated with increased carotid IMT with a focus on hyperhomocysteinemia. METHODS: This cross-sectional study included 1,222 patients who visited the Chung-Ang University Hospital Health Promotion Center from January 2013 to December 2015. The serum Hcy levels were estimated with a competitive immunoassay using the direct chemiluminescence method. The carotid IMT was measured by B-mode carotid ultrasonography. The definition of hyperuricemia was a serum uric acid level > 7.0 mg/dL for men or > 5.6 mg/dL for women, and hyperhomocysteinemia was defined as serum levels > 15 μmol/L. RESULTS: The hyperuricemic patients showed significantly higher serum Hcy levels and lower estimated glomerular filtration rate (eGFR) than did normouricemic patients (13.39 ± 4.42 vs. 11.69 ± 3.65 μmol/L, P < 0.001; 85.16 ± 19.18 vs. 96.14 ± 16.63, P < 0.001, respectively). Serum Hcy level (odds ratio [OR], 1.050; 95% confidence interval [CI], 1.009–1.092) and fasting glucose level (OR, 1.018; 95% CI, 1.011–1.026) were independent risk factors for carotid plaque. In patients with hyperuricemia, the serum Hcy levels correlated with the eGFR (γ = −0.478, P < 0.001). The carotid IMT correlated with serum Hcy levels and eGFR (γ = 0.196, P = 0.008; γ = − 0.297, P < 0.001, respectively) but not with the serum lipid profile. CONCLUSION: These results suggest that renal function impairment in hyperuricemic patients may worsen carotid IMT by increasing serum Hcy levels.