Serum Uric Acid Is Independently Associated with Metabolic Syndrome in Subjects with and without a Low Estimated Glomerular Filtration Rate

Abstract

The relationship among serum uric acid (SUA), metabolic syndrome, and chronic kidney disease (CKD) is unclear. We examined whether SUA level is an independent risk factor for chronic kidney disease and whether the association between SUA and metabolic syndrome is affected by kidney function. We analyzed 28,745 subjects (17,478 men, 11,267 women, age 20-49 yrs) who underwent health examinations at this hospital between 2000 and 2007. Hyperuricemia was defined as SUA level > 7.7 mg/dl in men or > 6.6 mg/dl in women. Kidney function was assessed by estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease Study equation modified for Chinese subjects. Impaired renal function with low GFR was defined as eGFR < 90 ml/min/1.73 m(2). The UA-low GFR groups were defined according to the observed combination of hyperuricemia and low GFR: Group A (absence of both hyperuricemia and low GFR); Group B (presence of low GFR but no hyperuricemia); Group C (presence of hyperuricemia but not low GFR); and Group D (presence of both hyperuricemia and low GFR). The prevalence of hyperuricemia, metabolic syndrome, and impaired kidney function with low GFR was 20.3% (27.6% in men, 8.9% in women), 7.6% (10.6% in men, 3.0% in women), and 9.9% (11.6% in men, 7.1% in women), respectively. The Pearson correlation between SUA and eGFR was only -0.26 (-0.21 in men, -0.22 in women; p < 0.001). In men, the age-adjusted odds ratio (OR) of metabolic syndrome was 1.41 (Group B), 2.45 (Group C), and 2.58 (Group D) in comparison with Group A. In women, the age-adjusted OR of metabolic syndrome was 0.83 (Group B), 5.47 (Group C), and 3.31 (Group D) in comparison with Group A. Hyperuricemia is prevalent in the Taiwan population. Hyperuricemia is only weakly associated with renal function, but is strongly associated with metabolic syndrome with or without a low eGFR.