Candidate for the Lee B. Lusted Student Prize Competition
Method: We developed a Markov model to calculate lifetime health benefits, costs, and incremental cost-effectiveness ratios (ICERs) of five urate-lowering treatment (ULT) strategies: 1) no treatment, 2) allopurinol single therapy, 3) febuxostat single therapy, 4) allopurinol- febuxostat sequential therapy, and 5) febusostat-allopurinol sequential therapy. We investigated two ULT dosing scenarios: 1) fixed dosing (febuxostat[80 mg daily] = 0.80 success rate; allopurionol [300 mg daily]= 0.39 success rate), 2) dose escalation (febuxsostat [up to 120mg daily] = 0.79 success rate; allopurionol [up to 700mg daily] = 0.78). Health states in the model reflected those that could occur during a gout patient’s lifetime: controlled (serum urate acid (SUA) <6.0 mg/dl), or uncontrolled (SUA ≥ 6.0 mg/dl). Within each state we accounted for gout flares and ULT associated adverse events, including allopurinol hypersensitivity syndrome. Costs were evaluated from a payer perspective. Cost and utility estimates were obtained from the literature and discounted by 3% per year. Gout flares and ULT associated adverse events were associated with a disutility. Sensitivity analyses were conducted to evaluate the impact of parameter uncertainty.
Result: In both (fixed and escalating) dosing scenarios, allopurinol as a single-line option was the least costly (discounted lifetime cost = $9,874 for fixed dosing; $9,348 for dose escalation) and was more effective than no treatment (cost-saving). In both dosing scenarios, allopurinol- febuxostat sequential therapy was more costly, but more effective than allopurinol single therapy, with an ICER of $72,900/QALY (fixed dosing) and $99,000/QALY (dose escalation). In both dosing scenarios, febusostat-allopurinol sequential therapy had a cost-effectiveness ratio >$500,000/QALY, and febuxostat single therapy cost more and was less effective than febusostat-allopurinol sequential therapy. Our results were sensitive to the utility difference between the controlled and uncontrolled states and febusostat cost. As the utility difference in increased from 0.03 (base case value) to 0.045, ICER for allopurinol- febuxostat sequential therapy became more favorable in both the fixed dosing ($48,500/QALY) and dose escalation ($65,600/QALY).
Conclusion: Allopurinol single therapy is cost-saving as compared with no treatment. Cost-effectiveness of allopurinol- febuxostat sequential therapy appears to be sensitive to the utility difference between the controlled and uncontrolled states and drug cost of febuxostat.
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