Cost Effectiveness of Controlled-Release Oxybutynin Compared with Immediate-Release Oxybutynin and Tolterodine in the Treatment of Overactive Bladder in the UK, France and Austria

Abstract

To estimate the cost effectiveness of controlled-release (CR) oxybutynin compared with immediate-release (IR) oxybutynin and tolterodine in the treatment of overactive bladder (OAB) in Austria, France and the UK. This was a modelling study on the management of patients with OAB who were >/=18 years of age, and had urge or mixed incontinence with a primary-urge component. The study was performed from the perspective of payers (i.e. the National Health Service [NHS] in the UK, Social Security in France and the Sick Funds in Austria) and patients. Clinical outcomes attributable to managing OAB were obtained from the published literature, and resource utilisation estimates were derived from a panel of clinicians. Using decision analytical techniques, three decision models were constructed depicting the management of OAB with CR oxybutynin, IR oxybutynin and tolterodine over 6 months in the UK, France and Austria. The models were used to estimate the cost effectiveness of CR oxybutynin relative to the other two anticholinergic drugs in each of the three countries and the expected direct patient costs and indirect societal costs (at 2000/2001 prices). Starting OAB treatment with CR oxybutynin instead of either IR oxybutynin or tolterodine in the UK and Austria was found to be a potentially dominant strategy, since it improves clinical outcome at a lower cost, from the payers' perspective. In France, starting OAB treatment with CR oxybutynin instead of either the IR formulation or tolterodine was found to be a potentially cost-effective strategy from the payer's perspective. The expected 6-monthly direct costs to patients were euro230, euro720-920 and euro970-1000 in the UK, France and Austria, respectively. In the UK and Austria, these costs were broadly consistent between initial treatments. However, in France, tolterodine-treated patients would be expected to incur 28% more expenditure than patients treated with the other two drugs. Transportation emerged as the primary cost driver, accounting for at least 60% of patients' out-of-pocket expenditure, in all three countries. Irrespective of the initial treatment, patients would be expected to miss 1-2 days of work over 6 months as a result of their OAB. This equates to an expected lost productivity cost of euro84, euro250 and euro98 in the UK, France and Austria, respectively. Starting OAB treatment with CR oxybutynin is expected to be a clinically more effective strategy than starting with either IR oxybutynin or tolterodine, and potentially the most cost-effective strategy in all three countries.