A Pharmacoeconomic Model Comparing Two Long-Acting Treatments for Overactive Bladder

OBJECTIVE: To compare the estimated first-line treatment costs of extended-release tolterodine versus controlled-release oxybutynin in patients with overactive bladder (OAB). METHODS: We developed a decision-analysis model to estimate the patterns of treatment, resource consumption, and cost impact of treating OAB with either controlled-release oxybutynin or extended-release tolterodine as first-line drug therapy. We used data from the published literature to develop the framework for the model and supplemented this information with expert opinion, where necessary. Based on recent clinical studies, we assumed equal efficacy between the comparators and reduced the model to a cost-minimization analysis. The model was constructed from the payer perspective, and all costs are given in 2000 U.S. dollars. RESULTS: A base-case analysis was generated showing that patients initiating therapy with extended-release tolterodine have probable average 3-month treatment costs of 1,207 dollars compared to 1,283 dollars for patients initiating with controlled-release oxybutynin, for a 6.3% difference. First-line OAB direct drug costs account for 19% and 15% of total costs for extended-release tolterodine and controlled-release oxybutynin, respectively. Sensitivity analysis showed these results to be relatively stable. CONCLUSION: The results from this analysis suggest that for patients with OAB and initiating long-acting pharmacologic therapy in the primary care setting, the treatment with extended-release tolterodine is slightly less costly than treatment with controlled-release oxybutynin. Studies directly comparing these treatment alternatives are needed, however, to determine which approach or combination of approaches is the most cost-effective.