Synergistic association of hyperuricemia and hyperhomocysteinemia with chronic kidney disease in middle-aged adults and the elderly population

Chronic kidney disease (CKD) is a major global public health issue. Both hyperhomocysteinemia (HHcy) and hyperuricemia are independent risk factors for CKD. In this study, we evaluated the association of HHcy and hyperuricemia with CKD in the middle-aged and elderly populations in Taiwan. In this cross-sectional study, we collected the data of 5910 patients aged >= 50 years after their self-paid health examination at a single medical center. Homocysteine (Hcy) levels were divided into 4 quartiles (Q1, <8.2; Q2, 8.2-9.8; Q3, 9.9-11.7; and Q4, >11.7 mu M/L). Renal function was determined using the Chronic Kidney Disease Epidemiology Collaboration equation. Patients were considered to have CKD if their estimated glomerular filtration rate was < 60 mL/min/1.73 m(2). The prevalence of CKD significantly increased with the quartiles of uric acid (UA) and Hcy. In multiple logistic regression analysis, the odds ratios (ORs) of CKD increased with the quartiles of Hcy, independent of UA. There was 22.9 in Q4 in the normal serum UA group and 18.3 in the hyperuricemia group compared with Q1 of Hcy. Both hyperuricemia (OR 2.9) and Q4 of Hcy (OR 8.1) were significant independent risk factors for CKD. Furthermore, hyperuricemia and HHcy had significant synergistic association (synergy index, 1.7) with CKD. The ORs of CKD increased with the quartiles of Hcy, independent of hyperuricemia. Hyperuricemia and HHcy had synergistic association with CKD.