Mildly decreased egfr modifies the association between uric acid and risk of kidney function decline: a 5-year population-based cohort study

Abstract Background the role of uric acid (UA) in chronic kidney disease (CKD) remains controversial. In this study, the effects of UA levels on risk of kidney function (KF) decline in patients with normal or mildly decreased KF at baseline were investigated. Methods Data were extracted from the community-based Tongzhou Cohort Study. The cohort of 4246 patients was divided into the normal KF group (estimated glomerular filtration rate [eGFR] ≥ 90 mL/min/1.73 m2) or mildly decreased KF group (60 ≤ eGFR < 90 mL/min/1.73 m2). The primary endpoint was the risk of kidney function decline, which defined as a composite of a ≥ 30% decrease in eGFR from baseline or new onset of CKD diagnosed during the annual checkups. Results A total of 284 participants reached the primary endpoint during the 5-year follow-up period. There was a significant interaction between UA levels and baseline eGFR (p < 0.001). Restricted cubic spline analysis revealed a U-shaped association between baseline UA levels and the risk of decreased KF for participants with normal KF (cut-off value = 5.0 mg/dL; pnonlinear = 0.025) and a linear association for participants with mildly decreased KF (pnonlinear = 0.384). The odds ratio of an increase in UA levels by 1 mg/dL was 1.15 [95% confidence interval (CI) 1.02–1.31, p = 0.028] for the primary endpoint and 1.15 (95% CI = 1.01–1.31, p = 0.037) for new onset of CKD for participants with mildly decreased KF. Conclusion The association between uric acid and risk of KF decline was U-shaped in participants with normal KF while linear in participants with mildly decreased KF.