RESUMEN
The objective of this study is to evaluate the cost effectiveness of two new treatments for overactive bladder: once-daily controlled-release oxybutynin, and twice-daily tolterodine, with a comparison with oxybutynin immediate release. Also estimated are the potential cost savings to a health plan budget resulting from increased utilization of the most cost-effective treatment. The design is a decision-tree model based on clinical trial data and expert panel estimates with a six-month time horizon conducted from a payer perspective. The primary outcome measure used in the analysis was treatment success, with success defined as zero incontinence episodes per week. A secondary outcome measure was the expected number of continent days. As first-line therapy, controlled-release oxybutynin is the most cost-effective treatment as measured by expected cost per success and expected cost per continent days. Controlled-release, once-daily oxybutynin yielded the highest expected success rate and the highest number of expected continent days. The expected cost of treatment with controlled-release oxybutynin was lower than tolterodine and equivalent to immediate-release oxybutynin. Increased utilization of controlled-release oxybutynin results in an estimated saving of $0.007 to $0.026 per member per month for a hypothetical HMO. The model was robust, incorporating all assumptions based on univariate and multivariate sensitivity analysis. Initiating treatment with controlled-release oxybutynin is the most cost-effective approach to treatment for overactive bladder.