Cost-Effectiveness of Allopurinol and Febuxostat for the Management of Gout

BACKGROUND: Gout is the most common inflammatory arthritis in the United States. OBJECTIVE: To evaluate the cost-effectiveness of urate-lowering treatment strategies for the management of gout. DESIGN: Markov model. DATA SOURCES: Published literature and expert opinion. TARGET POPULATION: Patients for whom allopurinol or febuxostat is a suitable initial urate-lowering treatment. TIME HORIZON: Lifetime. PERSPECTIVE: Health care payer. INTERVENTION: 5 urate-lowering treatment strategies were evaluated: no treatment; allopurinol- or febuxostat-only therapy; allopurinol-febuxostat sequential therapy; and febuxostat-allopurinol sequential therapy. Two dosing scenarios were investigated: fixed dose (80 mg of febuxostat daily, 0.80 success rate; 300 mg of allopurinol daily, 0.39 success rate) and dose escalation (≤120 mg of febuxostat daily, 0.82 success rate; ≤800 mg of allopurinol daily, 0.78 success rate). OUTCOME MEASURES: Discounted costs, discounted quality-adjusted life-years, and incremental cost-effectiveness ratios. RESULTS OF BASE-CASE ANALYSIS: In both dosing scenarios, allopurinol-only therapy was cost-saving. Dose-escalation allopurinol-febuxostat sequential therapy was more costly but more effective than dose-escalation allopurinol therapy, with an incremental cost-effectiveness ratio of $39 400 per quality-adjusted life-year. RESULTS OF SENSITIVITY ANALYSIS: The relative rankings of treatments did not change. Our results were relatively sensitive to several potential variations of model assumptions; however, the cost-effectiveness ratios of dose escalation with allopurinol-febuxostat sequential therapy remained lower than the willingness-to-pay threshold of $109 000 per quality-adjusted life-year. LIMITATION: Long-term outcome data for patients with gout, including medication adherence, are limited. CONCLUSION: Allopurinol single therapy is cost-saving compared with no treatment. Dose-escalation allopurinol-febuxostat sequential therapy is cost-effective compared with accepted willingness-to-pay thresholds. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality.