Detailed association between serum uric acid levels and the incidence of chronic kidney disease stratified by sex in middle-aged adults

Background and aims: Chronic kidney disease (CKD) is a global health burden. Previous studies have shown a J- or U-shaped association between serum uric acid (SUA) and cardiovascular mortality. We assessed the risk of CKD incidence in a refined SUA category in middle-aged adults stratified by sex. Methods: We analyzed data from 138,511 participants <65 years old (29.6% women; mean age 44.1 years) without CKD at baseline acquired from the JMDC database. The Cox model was used to assess the adjusted hazard ratio (HR). Results: During the mean follow-up period of 4.68 years, 12,589 participants developed CKD. The fully adjusted HRs (95% confidence interval [CI], p-value) for CKD incidence in men with SUA <4.0, 10.0-10.9 and > 11.0 mg/ dL compared to men with SUA 4.0-4.9 mg/dL were 1.13 (1.01-1.26, p = 0.030), 1.98 (1.32-2.97, p = 0.0010), and 3.74 (1.68-8.35, p = 0.0013), respectively. The fully adjusted HRs for CKD incidence in women with SUA <4.0, 8.0-8.9, and >9.0 mg/dL compared to women with SUA 4.0-4.9 mg/dL were 1.08 (1.01-1.16, p = 0.032), 2.39 (1.07-5.35, p = 0.034), and 3.20 (0.80-12.8, p = 0.10), respectively. Conclusions: Both high and low SUA levels were identified as risk factors for CKD incidence in middle-aged men and women. The association of SUA levels with the increase in the risk of CKD incidence differed by sex, and the range of SUA levels associated with an increase in the risk of CKD incidence varied by sex.