Aim: Uric acid (UA) is strongly associated with the confirmed chronic kidney disease (CKD) risk factors, such as hypertension, diabetes and metabolic syndrome (MS); however, whether higher UA is independently associated with CKD is still debatable. Other studies found that low UA level may reflect inadequate protection against oxidant-mediated stress; it is also unknown whether hypouricemia may have a harmful effect on the kidney. No studies have examined whether there is a J-shaped relationship between UA and incident CKD.
Methods: The association between UA and incident kidney disease (Glomerular filtration rate <60 mL/min per 1.73 m(2) ) was examined among 94 422 Taiwanese participants, aged ≥20 years with a mean 3.5 years follow-up in a retrospective cohort. The association between UA and CKD was evaluated using Cox models with adjustment for confounders.
Results: The adjusted hazard ratio (HR) for incident CKD was 1.03 (95% confidence interval (CI), 1.01 to 1.06) for baseline UA level (increase by 1 mg/dL). Compared with serum UA in the first quintile (2.0 to 4.5 mg/dL), the multivariate-adjusted HR for CKD of the fifth (≥7.3 mg/dL), fourth (6.3 to 7.2 mg/dL), third (5.5 to 6.2 mg/dL), second (4.6 to 5.4 mg/dL) and hyopuricemia (<2.0 mg/dL) were 1.15 (95%CI, 1.01-1.30), 0.98 (95%CI, 0.87-1.10), 1.06 (95%CI, 0.94-1.19), 1.02 (95%CI, 0.91-1.14) and 1.65(95%CI, 0.53-5.15), respectively. The tests for the non-linear association were all not significant for both male and female. Gender-specific model revealed only the UA above 7.3 mg/dL with the increased risk of new-onset CKD in males.
Conclusion: Hyperuricemia is a risk factor for CKD in Taiwan, future studies are still necessary to determine whether hypouricemia increases the risk of CKD.
© 2011 The Authors. Nephrology © 2011 Asian Pacific Society of Nephrology.