Background Febuxostat is a novel nonpurine selective inhibitor of xanthine oxidase. Its predominant hepatic metabolism is an advantage for patients with gout and chronic kidney disease (CKD), so no dose adjustment is needed. However, in clinical trials patients with severe CKD were excluded , so caution is advised in patients with a reduced estimated glomerular filtration rate (eGFR<30mL/min/1.73m2) .
Objectives To review our experience with febuxostat in patients with gout, and to assess outcomes in the subgroup with eGFR<30mL/min/1.73m2.
Methods Retrospective review. Clinical records of patients with crystal-proven gout treated with febuxostat (prescribed by a rheumatologist of the unit) were selected. Epidemiological, clinical and laboratory data were collected. Study variables were: a) the change in serum uric acid (SUA) levels after treatment with febuxostat; and b) the percentage of patients who attained SUA<6mg/dL; SUA<5mg/dL; and SUA<4mg/dL. Two time-points were determined: 1) first lab tests after starting febuxostat, and 2) 6 months after continuous treatment with febuxostat at its maximal dose used. Comparisons according to the eGFR value (above or below 30mL/min/1.73m2) at the start of febuxostat were performed using chi-square and Mann-Whitney's U tests.
Results Records from 55 patients with gout treated with febuxostat were reviewed, mean (p25-75) aged 73 years (63-84), being 70.9% men. Gout was tophaceous in 15 patients (27.3%). The maximal dose used of febuxostat was 80 mg/d in 68,5% of patients. Other urate lowering agent had been used in 38 patients (69.1%), being skin reactions the main reason for discontinuation (11 patients, 20%). In 14 patients (25.5%) febuxostat was started at a eGFR<30mL/min/1.73m2, but in no case it was below 15mL/min. The table shows the outcomes comparison regarding the eGFR values. SUA at baseline was found similar. No differences were found in the magnitude of SUA reduction after long-term febuxostat nor in the achievement of the different SUA endpoints. Variation in eGFR values was similar in both groups. Regarding safety concerns, in 11 patients febuxostat was discontinued (3 cases due to skin reactions, in one case also previously with allopurinol), but it did not differ regarding eGFR subgroups (p=0.33).
Conclusions Febuxostat appears effective and safe in patients with severe renal impairment (eGFR<30mL/min/1.73m2) and merit considering its use until these results are confirmed by prospective controlled studies.
Arthritis Rheum. 59:1540.
Adenuric® label, EMA.
Disclosure of Interest N. Quilis: None declared, S. Gil: None declared, M. Andrés: None declared, P. Vela: None declared, E. Pascual Consultant for: Menarini