Background Among inflammatory joint diseases, gout is a main cause of recidivism in urgency departments due to insufficient pain control or development of arthritis flares. This burden produces time and resources consumption and time of work off. New and old hypouricemic treatments are not only intended to control uric acid level below 6mg/dL but to reduce the number of flares per year. It is well known that their activity removing uric deposits could trigger new flares so prophylactic treatment is always recommended when those treatments are initiated. There are many studies conducted to compare hypouricemic effectiveness with those treatments, however, their impact in flare-free survival is a topic not previously studied.
Objectives To compare the effectiveness of Allopurinol and febuxostat in terms of recidivism in patients with gout flares.
Methods A descriptive retrospective study was performed. Electronic registries of patients diagnosed by gout and treated with Allopurinol (100–200mg/d and 300–600mg/d) and febuxostat (80mg/d and 120mg/d) with at least a gout flare were included. Prophylaxis treatment was considered as positive in patients on treatment with colchicine 0.5–1mg/día or NSAIDs according to the 2012 ACR Guidelines for management of gout (Khanna et al. Arthritis Care & Research, 2012: 64 (10); 1447–61). Follow up period was 2013–2015. Only patients with flares were included. Kaplan Meier curves were built considered censored any flare which took place after 6 months since the treatment started. Data recovered from electronic registries were: demographic and clinical data, number of consultations and work off time where appropriated. Comparisons were made according to hypouricemic treatment and colchicine prophylaxis treatment. No data about treatment compliance were considered.
Results 90 registries of different patients were identified: 18 were under treatment with febuxostat (14 on 80mg/day and 3 on 120mg/day) and 72 under treatment with allopurinol (22 on 100–200mg/day, 50 on 300–600mg/day). Difference on average of age, proportion of males and proportion of tophus were not statistically significant between both groups. Mean of time until the first flare after starting treatment with allopurinol was 132.4 SD 6.8 days (CI95% 119.0–145.8) and 142.6 SD 11.63 (CI95% 119.8–165.4) with febuxostat (Chi-squared 0.304; P=0.581, Hazard ratio 0.806; 95%CI 0.3935–1.654). Excluding patients without prophylaxis treatment (2 on febuxostat and 26 on allopurinol), the mean of time until the first flare was 116.4 SD 8.0 days (CI95% 100.7–132.1) in the group on allopurinol and 153.8 SD 9.9 days (CI95% 134.3–173.3) in the group on febuxostat (Chi-squared 5.984; P=0.0144, Hazard ratio 0.356 (CI95% 0.183–0.692). No differences statistically significant were observed when Kaplan Meier curves were built groping patients according to the doses of Allopurinol or febuxostat.
Conclusions Our observations point that there is a tendency to higher surveillance without flares in gouty patients on febuxostat than on allopurinol. This tendency becomes statistically significant when only patients on colchicine treatment were compared, so it seems that prophylaxis treatment benefits specially this group of patients prolonging the period of time free of flares.
Disclosure of Interest None declared