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

Abstract

Background: Both hyperttricemia 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 mu mol/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 mu mol/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 (gamma = -0.478, P< 0.001). The carotid IMT correlated with serum Hcy levels and eGFR (gamma = 0.196, P= 0.008; gamma = - 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.