The effects of long-term use of topiroxostat on serum uric acid levels and renal function in patients with hyperuricemia: A retrospective study

Abstract

This study investigated the effects of topiroxostat treatment on serum uric acid (UA) levels and estimated glomerular filtration rate (eGFR) in patients who received topiroxostat for at least 24 months for treatment of hyperuricemia and had an eGFR of less than 60 mL/min/1.73 m². Patients with mean serum UA levels ≤ 6 mg/dL after 12 months on topiroxostat were classified as the low UA group, and patients with mean UA levels above this cutoff at month 12 were classified as the high UA group. A total of 61 patients were included in the analysis. No significant changes in eGFR were observed in either group, and no significant differences in the change in eGFR (ΔeGFR) were found between these groups. Serum UA levels decreased significantly in the subgroups defined according to the glomerular filtration rate categories G3a and G3b at baseline. The ΔeGFR did not change significantly in the G3a subgroup (mean baseline serum UA level: 5.79 mg/dL), but it increased significantly by 2.1 mL/min/1.73 m² in the G3b subgroup (mean baseline serum UA level: 6.50 mg/dL ; p = 0.043). Long-term administration of topiroxostat significantly reduced serum UA levels. Although no differences were seen in eGFR between groups with low and high serum UA levels, a significant increase in eGFR was observed in patients who had high serum UA levels before treatment initiation. Topiroxostat may exert renal protective effects in patients with hyperuricemia with eGFR levels of less than 60 mL/min/1.73 m² who are not responding sufficiently to UA-lowering therapy.