LAUSR

Background Febuxostat is a new xanthine oxidase inhibitor which is effective in the treatment of hyperuricemia. Its use in people with different levels of renal function has not been thoroughly assessed. Objectives To assess the risk of renal function deterioration in gout patients using febuxostat and compare it with patients using allopurinol and other uricosuric agents. Methods We included 5882 adult patients with gout diagnosed between 2012 and 2015. We divided patients into three groups by usage of urate-lowering drugs used (allopurinol, febuxostat and uricosuric agents including benzbromarone, probenecid and sulfinpyrazone). The primary outcome was a progress of one chronic kidney disease (CKD) stage. The index date was the first date of urate-lowering drugs used. We follow each patient to the date of event, death, switch to other drug or the end of the study. The Cox proportional hazards model was used to estimate the adjusted hazard ratios (HRs), adjusted for age, sex, baseline eGFR, baseline serum urine acid, comorbidity, co-medication. Results The incident rate of the renal function deterioration was 2.37 (95% CI, 1.75–3.14) per 1000 person-days in allopurinol users, 1.54 (95% CI, 1.30–1.81) per 1000 person-days in febuxostat users and 1.43 (95% CI, 1.32–1.56) per 1000 person-days in uricosuric agent users. The HRs of progession of CKD stage in febuxostat and uricosuric agent users were 0.98 (95% CI, 0.70–1.38) and 0.80 (95% CI, 0.59–1.09) compared with allopurinol. Among febuxostat users, the HRs were 1.80 (95% CI, 0.85–3.98) in patients with an estimated glomerular filtration rate (eGFR) ≥90 ml/min/1.73 m2), 1.06 (95% CI, 0.56–2.03) for patients with an eGFR 60–89 ml/min/1.73 m2, 0.78 (95% CI, 0.45–1.42) for patients with an eGFR 30–59 ml/min/1.73 m2 and 0.73 (95% CI, 0.22–3.52) for patients with an eGFR 15–29 ml/min/1.73 m2. Among uricosutic agent users, the HRs were 0.94 (95% CI, 0.52–1.88) in patients with an eGFR ≥90 ml/min/1.73 m2, 0.88 (95% CI, 0.55–1.50) in patients with an eGFR 60–89 ml/min/1.73 m2, 0.71 (95% CI, 0.41–1.28) in patients with an eGFR 30–59 ml/min/1.73 m2 and 0.71 (95% CI, 0.19–3.62) in patients with an eGFR 15–29 ml/min/1.73 m2. Conclusions Renal function deterioration is not uncommon after initiation of urate-lowering treatment and febuxostat has a similar renal safety profile as allopurinols and uricosuric agents. Disclosure of Interest None declared