U-shaped relationship between uric acid and residual renal function decline in continuous ambulatory peritoneal dialysis patients.

Aim: There is little information on the relationship between uric acid (UA) and residual renal function (RRF) in continuous ambulatory peritoneal dialysis (CAPD). The aim of this research is to study the influence of UA on RRF decline in CAPD patients.

Methods: A retrospective observational cohort study of 304 patients who started CAPD without anuria between 2001 and 2010 was conducted at a single medical center. The outcomes measured in the study included the rate of RRF decline and anuria. A multiple ordinal logistic regression model with backward elimination was conducted to determine the independent factors of the slope of RRF decline. A Cox proportional hazard model was conducted to determine the independent variables of time to anuria.

Results: The average rate of RRF decline was -0.12 ± 0.22 mL/min per month. Multivariate analysis showed that lower UA group (<0.372 mmol/L), higher UA group (≧0.421 mmol/L), male gender, diabetes mellitus (DM), the use of calcium channel blocker (CCB), and RRF at baseline were linked positively with the rate of RRF decline; on the other hand, independence in dialysate exchanges and BUN were negatively associated with the risk of RRF decline. In addition, male gender, DM, diuretics, and CCB were associated with a higher risk of progression to anuria, whereas 24-h urine amount at baseline conferred a protective role in the development of anuria.

Conclusions: A U-shaped relationship was found between UA levels and the rate of RRF decline in patients on CAPD, with a faster decline rate in those of higher and lower UA groups.