Objective: To determine in a Canadian health care setting the cost effectiveness of urate lowering drugs (ULD) in the treatment of nontophaceous gouty arthritis with recurrent attacks and to evaluate the least costly regimen among available ULD.
Methods: A decision analysis model was designed using hypothetical cohort of patients who present 1 to 4 recurrent attacks/year. It incorporated costs and probabilities estimated from the published literature. Effectiveness was defined as the number of recurrent attacks averted by each treatment strategy (ULD or No ULD). The incremental cost effectiveness ratio was defined as the ratio of the additional cost incurred by a management strategy compared with the additional benefit derived from it. A multiway sensitivity analysis was built to allow the modelling of extreme case scenarios favoring (best ULD scenario) and disfavoring (worst ULD scenario) the ULD therapy.
Results: Using the baseline scenario estimates for the hypothetical cohort of patients presenting one attack/year, the total annualized costs per patient associated with ULD and No ULD treatment were Cdn $426.27 and 267.27, respectively. The average cost effectiveness ratios were $592.25 and 5,345.37, respectively, per attack averted. For this cohort of patients the incremental cost effectiveness ratio ranged from $99.59 (best ULD scenario) to 489.26 (worst ULD scenario). The treatment with ULD is cost saving if patients present 2 or more attacks/year. Allopurinol in its generic formulation was the ULD that presented the lowest incremental cost effectiveness ratio.
Conclusion: ULD treatment is cost effective. It is also saving if patients present 2 or more recurrent attacks/year.