A cost-utility analysis of once daily solifenacin compared to tolterodine in the treatment of overactive bladder syndrome

Objective: To evaluate the cost-utility of solifenacin, a new generation antimuscarinic, compared with tolterodine in the treatment of overactive bladder syndrome (OAB), from the perspective of the UK National Health Service (NHS). Research design and methods: A 1-year Markov model was constructed using data from a 12-week, randomised, double-blind study that compared flexible dosing with solifenacin (5 mg and 10 mg) with tolterodine (IR 2 mg bd/ER 4 mg) in adults with DAB. The model incorporated five discrete health states that were based on disease severity (micturitions/day and incontinence episodes/day). A 'drop out' state was also used in the model to account for patients that discontinued treatment in the first year. UK-specific costs for drug treatment and pad use as well as utilities were assigned to each health state. Results: Solifenacin was a less costly and more effective treatment strategy compared with tolterodine. During the course of 1 year, the estimated cost per patient was 2509 for patients treated with solifenacin and 526 pound for those given tolterodine, a cost saving of El 7 per patient. Treatment with solifenacin was also associated with a small incremental gain of 0,004 quality-adjusted-life-years (QALYs) over tolterodine. Sensitivity analysis suggests that the incremental cost effectiveness of solifenacin relative to tolterodine does not appear to exceed 30 pound 000/QALY with even large variations in key model parameters. Conclusion: Flexible dosing with solifenacin is likely to be cost-effective versus tolterodine in the treatment of DAB. Further studies are needed to confirm these results.