Preservation of renal function during gout treatment with febuxostat: a quantitative study.

BACKGROUND: Hyperuricemia can accelerate renal decline associated with aging. Chronic kidney disease is frequently seen in patients with hyperuricemia and gout.

OBJECTIVES: Assess the impact of urate-lowering therapy on renal function in subjects with gout who were treated with febuxostat for ≤ 48 months.

METHODS: Subjects from 2 phase 3 clinical studies were enrolled in the phase 3, long-term, open-label Febuxostat/Allopurinol Comparative Extension Long-Term (EXCEL) study. In the EXCEL study, 1086 subjects initially were treated with febuxostat 80 or 120 mg daily, or allopurinol 300 mg daily. The subjects were permitted to switch between doses of febuxostat and/or allopurinol during the first 6 months of treatment to achieve and maintain a serum uric acid (SUA) level ≥ 3 to < 6 mg/dL. For the analysis presented in this article, data from 551 subjects who received only febuxostat throughout the duration of both the phase 3 and EXCEL studies (≤ 48 months) were used to determine the impact of SUA reduction on estimated glomerular filtration rates (eGFRs).

RESULTS: At baseline of the 2 original phase 3 studies, subjects' mean SUA level was 9.8 mg/dL. Greater sustained decreases in subjects' SUA levels were associated with less renal function decline (P < 0.001) by statistical modeling. The study data predicted that for every 1 mg/dL of chronic reduction of SUA level in subjects with gout, there would be a preservation of 1.15 mL/min of eGFR.

CONCLUSION: Sustained urate-lowering therapy with febuxostat appears to impede renal decline in patients with gout. The results discussed in this article support similar observations previously reported in 116 hyperuricemic subjects with gout who received febuxostat for ≤ 5 years.