Achieving Serum Urate Goal: A Comparative Effectiveness Study Between Allopurinol and Febuxostat

Background: Febuxostat is recommended as 1 of 2 first-line urate-lowering therapies (ULT) for treating gout in the 2012 American College of Rheumatology Guidelines. Several efficacy trials have compared febuxostat with allopurinol treatment, but real-world comparative data are limited. Methods: We compared effectiveness of the 2 agents in reaching serum urate (sUA) level goal (< 6 mg/dL) within 6 months (main endpoint), factors impacting the likelihood of reaching goal, and outcomes in allopurinol patients who were switched to febuxostat therapy after failing to reach sUA level goal. Data from the General Electric Electronic Medical Record database on adult patients with newly diagnosed gout, who had started treatment with allopurinol or febuxostat in 2009 or thereafter were analyzed. Descriptive statistics, bivariate analyses, and logistic regressions were used. Results: Allopurinol (n = 17 199) and febuxostat (n = 1190) patients had a mean +/- standard deviation (SD) age of 63.7 (+/- 13.37) years; most patients were men and white. Average daily medication doses (mg) in the first 6 months were 184.9 +/- 96.7 and 48.4 +/- 15.8 for allopurinol-and febuxostat-treated patients, respectively; 4.8% of allopurinol-treated patients switched to febuxostat, whereas 25.7% of febuxostat-treated patients switched to allopurinol. Febuxostat patients had lower estimated glomerular filtration rate levels, more diabetes mellitus, or tophi at baseline (P< 0.05) and 29.2% and 42.2% of patients in the allopurinol and febuxostat groups achieved goal sUA levels (P < 0.0001). Febuxostat was significantly more effective in patients reaching sUA goal (adjusted odds ratio, 1.73; 95% CI, 1.48-2.01). Older patients and women had greater likelihood of reaching sUA goal level; however, patients with higher Charlson Comorbidity Index scores, blacks, or those with estimated glomerular filtration rates between 15 to <= 60 mL/min had reduced likelihood of attaining goal (P, 0.05). Among allopurinol-treated patients who were switched to febuxostat after failing to reach goal, 244 (48.3%) reached goal on febuxostat (median = 62.5 days), with an average 39% sUA level reduction achieved within 6 months. Patients who did not reach goal had a 14.3% sUA level reduction.Conclusions: The real-life data support the effectiveness of febuxostat in managing patients with gout.