Cost-Effectiveness of tolterodine for patients with urge incontinence who discontinue initial therapy with oxybutynin: a Canadian perspective.
BACKGROUND
Tolterodine is a novel muscarinic receptor antagonist for the treatment of overactive bladder.


OBJECTIVE
The purpose of this study was to examine the cost-effectiveness of tolterodine for patients with urge incontinence (UI) who discontinue initial therapy with oxybutynin in a Canadian setting.


METHODS
We compared 2 treatment strategies for the management of adult patients with UI: (1) generic oxybutynin with no further treatment for patients who discontinue and (2) generic oxybutynin with switch to tolterodine (2 mg BID) for patients who discontinue. We developed a 1-year Markov model (4-week cycle length) with transitions between disease states of normal, mild, moderate, and severe. Transition probabilities over 12 weeks were obtained from randomized trial data, and drug discontinuation rates were obtained from Quebec prescription claims data. Outcome measures were time in "normal" health state and quality-adjusted life-years (QALYs) using EuroQol-5D utility scores from a survey of Swedish patients with overactive bladder. Costs to the health care payer and patient out-of-pocket costs (in Canadian dollars) were included.


RESULTS
For patients who discontinue oxybutynin, the use of tolterodine is associated with approximately 6 months per year in a normal health or mild disease state, compared with approximately 3 months for those who do not receive further drug therapy after discontinuation. Tolterodine use resulted in an annual additional cost per patient of Can $163. The incremental cost per QALY was Can $9,982 and appeared to be robust to alternative model parameter assumptions.


CONCLUSIONS
Use of tolterodine in patients with UI who discontinue initial therapy with generic oxybutynin lies within currently accepted benchmarks for cost-effectiveness.
O'Brien
B J
BJ
Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada. obrienb@mcmaster.ca
Goeree
R
R
Bernard
L
L
Rosner
A
A
Williamson
T
T
D001559:Benzhydryl Compounds / Q000191:economics / Q000627:therapeutic use*; D002170:Canada; D003362:Cost-Benefit Analysis; D003408:Cresols / Q000191:economics / Q000627:therapeutic use*; D017850:Economics, Pharmaceutical; D006801:Humans; D008333:Mandelic Acids / Q000191:economics / Q000627:therapeutic use*; D008390:Markov Chains; D018727:Muscarinic Antagonists / Q000191:economics / Q000627:therapeutic use*; D010276:Parasympatholytics / Q000191:economics / Q000627:therapeutic use*; D010665:Phenylpropanolamine; D019057:Quality-Adjusted Life Years; D016032:Randomized Controlled Trials as Topic; D012720:Severity of Illness Index; D000068737:Tolterodine Tartrate; D014549:Urinary Incontinence / Q000145:classification / Q000188:drug therapy* / Q000191:economics
D001559:Benzhydryl Compounds; D003408:Cresols; D008333:Mandelic Acids; D018727:Muscarinic Antagonists; D010276:Parasympatholytics; D010665:Phenylpropanolamine; D000068737:Tolterodine Tartrate; C005419:oxybutynin