Effect of urate-lowering therapy on renal function in chronic kidney disease stages 2-5 patients with hyperuricemia

Objective To investigate the effect of urate-lowering therapy on renal function in chronic kidney disease (CKD) stages 2-5 patients with hyperuricemia (HUA). Methods A total of 132 patients of CKD stages 2-5 with HUA between July 2016 and December 2017 in Department of Nephrology of the Second Affiliated Hospital of Anhui Medical University were prospectively and self-controlled analyzed. Serum uric acid (SUA), estimated glomerular filtration rate (eGFR) and other clinical parameters were measured at baseline and after 1-6 months treatment. The patients were divided into group A (CKD stages 2-3a) and group B (CKD stages 3b-5) on the baseline value of eGFR. The changes of SUA and eGFR before and after treatment were compared. According to the level of SUA after 6 months treatment, patients were divided into attainment group (SUA<360 μmol/L) and nonattainment group (SUA≥360 μmol/L). The difference of renal function in pre-treatment and post-treatment was compared. Multiple stepwise linear regression was used to analyze the relationship among the change of eGFR after receiving 6 months' treatment (deGFR) and SUA level, baseline eGFR and other indexes. Results After 1, 3, 6 months treatment, the average levels of SUA, Scr and urea nitrogen of all patients were decreased significantly while eGFR value was increased significantly (all P<0.050) than those in pre-treatment period. After six-month-therapy, proteinuria and hematuria were improved significantly in all patients (P<0.001, P=0.001). Compared with pre-treatment period, both the SUA levels of group A and group B were declined significantly while eGFR had a significant rise after treatment (P<0.001). The change of eGFR post-treatment in group A was significantly higher than that of group B [(13.64±15.35) vs (8.97±9.79) ml·min-1·(1.73 m2)-1, P=0.044]. At 6 months after treatment, the eGFR value increased markedly in both attainment group and nonattainment group compared with pre-treatment period (P<0.001). After six-month-therapy, the eGFR value in attainment group was increased more obviously than that of nonattainment group [(13.96±14.64) vs (8.03±9.69) ml·min-1·(1.73 m2)-1, P=0.021]. Multiple stepwise linear regression analysis showed that the baseline eGFR value was an influencing factor of deGFR (b=0.161, P=0.020). Conclusions The renal function of CKD stages 2-5 patients with HUA can be significantly improved by urate-lowering therapy, which can effectively reduce proteinuria and hematuria. Key words: Kidney disease, chronic; Hyperuricemia; Therapeutics; Renal function