title: Cost-effectiveness analysis of solifenacin versus oxybutynin immediate-release in the treatment of patients with overactive bladder in the United Kingdom.
abstract: OBJECTIVE
  To carry out a cost-utility analysis comparing initial treatment with solifenacin 5 mg/day vs oxybutynin immediate-release (IR) 15 mg/day for the treatment of patients with overactive bladder (OAB) from the perspective of the U.K. National Health Service (NHS).
  
  
  METHODS
  A Markov model with six health states was developed to follow a cohort of OAB patients treated with either solifenacin or oxybutynin during a 1-year period. Costs and utilities were accumulated as patients transited through the health states in the model and a drop-out state. Some of the solifenacin patients were titrated from 5 mg to 10 mg/day at 8 weeks. A proportion of drop-out patients were assumed to continue treatment with tolterodine ER. Utility values were obtained from a Swedish study and pad use was based on a multinational clinical trial. Adherence rates for individual treatments were derived from a U.K. database study. For pad use and utility values, the drop-out state was split between those patients who were no longer receiving treatment and those on second-line therapy. Patients on second-line therapy who drop-out were referred for a specialist visit. Results were expressed in terms of incremental cost-utility ratios.
  
  
  RESULTS
  Total annual costs for solifenacin and oxybutynin were £504.30 and £364.19, respectively. First-line drug use represents 49% and 4% of costs and pad use represent 23% and 40% of costs for solifenacin and oxybutynin, respectively. Differences between cumulative utilities were small but were greater for solifenacin (0.7020 vs. 0.6907). The baseline incremental cost-effectiveness ratio was £12,309/QALY.
  
  
  CONCLUSIONS
  Under the baseline assumptions, solifenacin would appear to be cost-effective with an incremental cost-utility of less than £20,000/QALY. However, small differences in utility between the alternatives and the large number of drop-outs means that the results are sensitive to small adjustments in the values of utilities assigned to the drop-out state.
authors.affiliation: EcoStat Consulting UK , Norfolk , UK.
authors.forename: Warren Mark
authors.initials: WM
authors.lastname: Hart
authors.forename: Paul
authors.initials: P
authors.lastname: Abrams
authors.forename: Vicki
authors.initials: V
authors.lastname: Munro
authors.forename: Peny
authors.initials: P
authors.lastname: Retsa
authors.forename: Jameel
authors.initials: J
authors.lastname: Nazir
mesh_terms: D001559:Benzhydryl Compounds / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics*; D015331:Cohort Studies; D003362:Cost-Benefit Analysis; D003408:Cresols / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics*; D006801:Humans; D016496:Incontinence Pads / Q000191:economics / Q000706:statistics & numerical data; D008333:Mandelic Acids / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics*; D008390:Markov Chains; D018803:Models, Economic; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics; D010352:Patient Dropouts / Q000706:statistics & numerical data; D010665:Phenylpropanolamine / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics*; D019057:Quality-Adjusted Life Years; D011812:Quinuclidines / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics*; D000069464:Solifenacin Succinate; D044005:Tetrahydroisoquinolines / Q000008:administration & dosage / Q000009:adverse effects / Q000191:economics*; D000068737:Tolterodine Tartrate; D016896:Treatment Outcome; D006113:United Kingdom; D053201:Urinary Bladder, Overactive / Q000150:complications / Q000188:drug therapy* / Q000191:economics*; D014549:Urinary Incontinence / Q000188:drug therapy / Q000191:economics* / Q000209:etiology; D016903:Drug Monitoring
chemical_list: D001559:Benzhydryl Compounds; D003408:Cresols; D008333:Mandelic Acids; D018727:Muscarinic Antagonists; D011812:Quinuclidines; D044005:Tetrahydroisoquinolines; D010665:Phenylpropanolamine; D000068737:Tolterodine Tartrate; C005419:oxybutynin; D000069464:Solifenacin Succinate