INTRODUCTION

Xanthine oxidase (XO) inhibitors may slow down chronic kidney disease (CKD) progression. The comparative effectiveness of the different urate-lowering drugs is unknown. The aim of this study was to determine whether urate-lowering therapy with an XO inhibitor (febuxostat) and that with a uricosuric drug (benzbromarone) are comparable in slowing renal function decline in patients with CKD complicated with hypertension and hyperuricemia.

METHODS

This study was an open-label randomized parallel-group clinical trial of 95 patients with stage G3 CKD in Japan. The patients had hypertension and hyperuricemia without a history of gout. They were randomized to receive febuxostat ( n  = 47; febuxostat group) or benzbromarone ( n  = 48; benzbromarone group) and titrated to reduce their serum urate level to <6.0 mg/dl. The primary end-point was change in estimated glomerular filtration rate (eGFR) from baseline to 52 weeks. The secondary end-points included changes in uric acid level, blood pressure, urinary albumin-to-creatinine ratio, and XO activity.

RESULTS

Of the 95 patients, 88 (92.6%) completed the trial. There were no significant differences in change in eGFR (in ml/min/1.73 m 2 ) between the febuxostat [-0.23, 95% confidence interval (CI), -2.00 to 1.55] and benzbromarone (-2.18, 95% CI, -3.84 to -0.52) groups (difference, 1.95; 95% CI, -0.48 to 4.38; P  = 0.115) nor in the secondary end-points, except for XO activity. Febuxostat significantly reduced XO activity ( P  = 0.010). There were no significant differences in primary and secondary outcomes between the groups. A decrease in eGFR was significantly less in the febuxostat group than that of the benzbromarone group in the CKDG3a, but not in CKDG3b, in the subgroup analysis. There were no adverse effects specific to either drug.

CONCLUSIONS

No significant differences were found in the effects of febuxostat and benzbromarone in renal function decline in stage G3 CKD complicated with hyperuricemia and hypertension.