Cost effectiveness of mirabegron compared with tolterodine extended release for the treatment of adults with overactive bladder in the United Kingdom.

BACKGROUND: Overactive bladder (OAB) is highly prevalent and is associated with considerable morbidity and reduced health-related quality of life. ß3-adrenergic receptor (ß3-AR) stimulation is a novel alternative to antimuscarinic therapy for OAB. OBJECTIVE: The objective of this analysis was to assess the cost effectiveness of the ß3-AR agonist mirabegron relative to tolterodine extended release (ER) in patients with OAB from a UK National Health Service (NHS) perspective. METHODS: A Markov model was developed to simulate the management, course of disease, and effect of complications in OAB patients over a period of 5 years. Transition probabilities for symptom severity levels and probabilities of adverse events were estimated from the results of the randomised, double-blind SCORPIO trial in 1,987 patients with OAB. Other model inputs were derived from the literature and on assumptions based on clinical experience. RESULTS: Total 5-year costs per patient were £1,645.62 for mirabegron 50 mg/day and £1,607.75 for tolterodine ER 4 mg/day. Mirabegron was associated with a gain of 0.009 quality-adjusted life-years (QALYs) with an additional cost of £37.88. The resulting incremental cost-effectiveness ratio (ICER) was £4,386/QALY gained. In deterministic sensitivity analyses in the general OAB population and several subgroups, ICERs remained below the generally accepted willingness-to-pay (WTP) threshold of £20,000/QALY gained. The probability of mirabegron 50 mg being cost effective relative to tolterodine ER 4 mg was 89.4 % at the same WTP threshold. CONCLUSIONS: Mirabegron 50 mg/day is likely to be cost effective compared with tolterodine ER 4 mg/day for adult patients with OAB from a UK NHS perspective.

Cost-effectiveness analysis of solifenacin versus oxybutynin immediate-release in the treatment of patients with overactive bladder in the United Kingdom.

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. CONCLUSION: 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.

Cost-effectiveness analysis of solifenacin flexible dosing in patients with overactive bladder symptoms in four Nordic countries.

OBJECTIVE: The purpose of the present analysis was to analyze and compare the cost-effectiveness of solifenacin flexible dosing (5-10 mg) with tolterodine 4 mg sustained release (SR) or placebo (assumed to be comparable to no treatment) for patients with overactive bladder (OAB) symptoms. DESIGN: A decision-analytic model was constructed. METHODS: Costs and effects were evaluated for the three treatment options in a one-year timeframe. Costs included were treatment costs, cost of pad use, and patients productivity loss based on data from the Nordic countries. SAMPLE: Results from two randomized controlled trials were used as input data in the cost-effectiveness analysis. MAIN OUTCOME MEASURES: Quality adjusted life years and incremental cost-effectiveness ratio. RESULTS: Solifenacin flexible dosing was more effective with respect to reducing OAB symptoms compared to both placebo and tolterodine 4 mg. Treatment with both solifenacin and tolterodine was more costly compared to placebo, but treatment with solifenacin was a less costly alternative compared to tolterodine 4 mg SR. Sensitivity analyses revealed that the conclusions were robust. CONCLUSION: Solifenacin flexible dosing was a cost-effective treatment alternative compared to tolterodine 4 mg SR.

Persistence, adherence, and switch rates among extended-release and immediate-release overactive bladder medications in a regional managed care plan.

BACKGROUND: Pharmacotherapy constitutes an important adjunct to behavioral therapy for the treatment of overactive bladder (OAB). Tolterodine and oxybutynin are commonly prescribed drugs for OAB treatment that exert their beneficial effect by suppressing bladder muscle contractions. However, high discontinuation rates have been observed for these drugs in clinical trials, as well as in real-world settings, in part due to adverse effects. Extended-release (ER) formulations were introduced with an improved tolerability profile over immediate-release (IR) versions of the 2 drugs. No study has compared persistence and adherence to therapy for both the ER and IR versions of tolterodine and oxybutynin. OBJECTIVE: To compare persistence, adherence, and switch rates for the IR and ER formulations of oxybutynin and tolterodine for patients enrolled in a regional managed care plan. METHODS: Study patients were adults (aged e 18 years), with at least 1 pharmacy claim for either tolterodine extended-release (tol-ER), oxybutynin extended-release (oxy-ER), tolterodine immediate-release (tol-IR), or oxybutynin immediate-release (oxy-IR) during the period from July 1, 1999, to December 31, 2003, and were continuously eligible for benefits from 6 months before through 12 months after the initial OAB pharmacy claim (index) date. A retrospective cohort study design was used following patients from the index date to the occurrence of non-persistence with the index medication (i.e., a gap of > 45 days between successive prescription fills or a switch to any other OAB medication), or the end of a 1-year follow-up period, through December 31, 2004. Switching was defined as any change from the index medication, including a change in dose form (e.g., tol-IR to tol-ER), to one of the other 3 study drugs, or to a different OAB treatment (e.g., trospium chloride, oxybutynin patch, flavoxate, hyoscyamine sulfate, or propantheline bromide) during the follow-up period. Adherence was measured as the proportion of patients with a medication possession ratio (MPR) of at least 80%. MPR was calculated as (1) the sum of days supply for all pharmacy claims except the last pharmacy claim, divided by (2) the total number of days from the first fill date to the fill date of the last pharmacy claim. The association of drug therapy with study outcomes was assessed with bivariate and adjusted (multivariate) analyses. Multivariate analyses controlled for demographic and clinical characteristics, plan type, patient out-of-pocket cost for the index medication, and year of therapy initiation. RESULTS: 1,117 patients had at least 1 pharmacy claim for an OAB study drug (n = 454 for tol-ER [40.6%], n = 249 for oxy-ER [22.3%], n = 306 for tol-IR [27.4%], n = 108 for oxy-IR [9.7%]), of whom 81.6% were women. The mean (standard deviation [SD]) age of the study population was 55.7 (14.5) years. Only 53.7% had at least 1 OAB diagnosis recorded during the 18-month eligibility period. 44.5% of patients did not have a refill after the initial (index) pharmacy claim (39.4% for oxy-ER, 42.7% for tol-ER, 46.1% for tol-IR, and 59.3% for oxy-IR; P = 0.004). Only 13.2% persisted with treatment for at least 1 year (tol-ER = 15.0%, oxy-ER = 15.3%, tol-IR = 11.4%, oxy-IR = 6.5%; P = 0.050). The median days to discontinuation (non-persistency) were 31.0 overall, 33.0 for tol-ER, 34.0 for oxy-ER, 32.0 for tol-IR, and 0 for oxy-IR; P = 0.010. The overall switch rate as a percentage of all study patients was 13.3%, ranging from 9.9% for tol-ER, 13.7% for tol-IR, 16.5% for oxy-ER, and 19.4% for oxy-IR; P = 0.020. Of patients who refilled their initial prescription at least once, 24.0% made a medication switch. Adherence rates as measured by percentage of patients with MPR >or= 80% were 30.3% overall and higher for the ER formulations: 35.2% for tol-ER, 36.1% for oxy-ER, 23.5% for tol-IR, and 14.8% for oxy-IR; P < 0.001. CONCLUSIONS: Adherence was significantly better for ER than IR agents. The high rate of non-persistence (44.5%) following the first (index) prescription highlights the need for medication counseling by health care professionals.

Impact of solifenacin on resource utilization, work productivity and health utility in overactive bladder patients switching from tolterodine ER.

OBJECTIVE: Assess changes in resource utilization, work and activity impairment, and health utility among OAB patients continuing to have urgency symptoms with tolterodine ER 4 mg and willing to try solifenacin 5/10 mg. RESEARCH DESIGN AND METHODS: This was an open-label, non-comparative, flexible-dosing, multicenter, 12-week study assessing the efficacy and safety of solifenacin 5/10 mg/day. Patients receiving tolterodine ER 4 mg/day for >/=4 weeks but continuing to experience residual urgency symptoms (>/=3 urgency episodes/24 h) were enrolled into the study. After a 14-day washout, patients began treatment with solifenacin 5 mg/day with dosing adjustments allowed at Weeks 4 and 8. MAIN OUTCOME MEASURES: Outcomes were assessed using the Work Productivity and Activity Impairment Questionnaire - Specific Health Problem (WPAI-SHP), Health Utilities Index (HUI), and a resource utilization questionnaire administered at Pre-Washout and Week 12. RESULTS: Patients (n=440) reported significantly fewer physician office visits (p<0.0001), UTIs (p<0.0001), and pads/diapers (p=0.0009) during the study period while receiving solifenacin 5/10 mg/day, compared with the Pre-Washout period when receiving tolterodine ER 4 mg/day. After 12 weeks of treatment with solifenacin 5/10 mg/day, patients reported a reduction in work time missed (p=0.0017), less impairment while working (p<0.0001), less overall work impairment (p<0.0001) and a reduction in activity impairment (p<0.0001) compared to Pre-Washout. There was no significant difference in health utility scores. Treatment-emergent adverse events were mostly anticholinergic in nature, and were mild to moderate in severity. CONCLUSION: Overall, solifenacin 5/10 mg/day improved work productivity, activity participation, and reduced medical care use in OAB patients who continued to have urgency symptoms with tolterodine ER 4 mg/day and wished to switch to solifenacin 5/10 mg. This was an open-label, non-comparative study; therefore, further research is needed to confirm these results.

Final report on the safety assessment of sodium p-chloro-m-cresol, p-chloro-m-cresol, chlorothymol, mixed cresols, m-cresol, o-cresol, p-cresol, isopropyl cresols, thymol, o-cymen-5-ol, and carvacrol.

Sodium p-Chloro-m-Cresol, p-Chloro-m-Cresol (PCMC), Mixed Cresols, m-Cresol, o-Cresol, p-Cresol, Isopropyl Cresols, Thymol, Chlorothymol, o-Cymen-5-ol, and Carvacrol are substituted phenols used as cosmetic biocides/preservatives and/or fragrance ingredients. Only PCMC, Thymol, and o-Cymen-5-ol are reported to be in current use, with the highest concentration of use at 0.5% for o-Cymen-5-ol in perfumes. The use of PCMC in cosmetics is restricted in Europe and Japan. Cresols can be absorbed through skin, the respiratory tract, and the digestive tract; metabolized by the liver; and excreted by the kidney as glucuronide and sulfate metabolites. Several of these cresols increase the dermal penetration of other agents, including azidothymidine. In acute oral toxicity studies, LD50 values were in the 200 to 5000 mg/kg day-1 range across several species. In short-term studies in rats and mice, an o-Cresol, m-Cresol, p-Cresol or m-Cresol/p-Cresol mixture at 30,000 ppm in the diet produced increases in liver and kidney weights, deficits in liver function, bone marrow hypocellularity, irritation to the gastrointestinal tract and nasal epithelia, and atrophy of female reproductive organs. The no observed effect levels (NOEL) of o-Cresol was 240 mg/kg in mink and 778 mg/kg in ferrets in short-term feeding studies, with no significant dose-related toxicity (excluding body weight parameters). In mice, 0.5% p-Cresol, but neither m-Cresol nor o-Cresol, caused loss of pigmentation. Short-term and subchronic oral toxicity tests performed with various cresols using mice, rats, hamsters, and rabbits resulted in no observed adverse effect levels (NOAELs) for mice of 625 ppm and rats of 50 mg/kg day-1, although the NOEL was 2000 ppm in a chronic study using rats. In rabbits, < or =160 mg/kg PCMC was found to produce irritation and erythema, but no systemic effects. Hamsters dosed with 1.5% p-Cresol in diet for 20 weeks had a greater incidence of mild and moderate forestomach hyperplasia as compared to the control. Acute inhalation toxicity studies using rats yielded LC50 values ranging from >20 mg/m(3) for o-Cresol to >583 mg/m(3) for PCMC. No deaths were recorded in mice given o-Cresol at 50 mg/m(3). Cats exposed (short-term) to 9 to 50 mg/m(3) of o-Cresol developed inflammation and irritation of the upper respiratory tract, pulmonary edema, and hemorrhage and perivascular sclerosis in the lungs. Rats exposed (subchronic) to o-Cresol at 9 mg/m(3) had changes in leukocytes, spinal cord smears, nervous activity, liver function, blood effects, clinical signs, and neurological effects. In guinea pigs, exposure to 9 mg/m(3) produced changes in hemoglobin concentrations and electrocardiograms (EKGs). Rats exposed (subchronic) to 0.05 mg/m(3) Mixed Cresols by inhalation exhibited central nervous system (CNS) excitation, denaturation of lung protein, and decreased weight gain. All cresols appear to be ocular irritants. Numerous sensitization studies have been reported and most positive reactions were seen with higher concentrations of Cresol ingredients. Developmental toxicity is seen in studies of m-Cresol, o-Cresol, and p-Cresol, but only at maternally toxic levels. In a reproductive toxicity study of a mixture of m-Cresol and p-Cresol using mice under a continuous breeding protocol, 1.0% caused minimal adult reproductive and significant postnatal toxicity in the presence of systemic maternal toxicity. The o-Cresol NOAEL was 0.2% for both reproductive and general toxicity in both generations. Cresol ingredients were generally nongenotoxic in bacterial, fruit fly, and mammalian cell assays. Thymol did not induce primary lung tumors in mice. No skin tumors were found in mice exposed dermally to m-Cresol, o-Cresol, or p-Cresol for 12 weeks. In the trypthan blue exclusion assay, antitumor effects were observed for Thymol and Carvacrol. Clinical patch testing with 2% PCMC may produce irritant reactions, particularly in people with multiple patch test reactions, that are misinterpreted as allergic responses. o-Cresol, p-Cresol, Thymol, Carvacrol, and o-Cymen-5-ol caused no dermal irritation at or above use concentrations. In two predictive patch tests, PCMC did not produce a sensitization reaction. Overall, these ingredients are not significant sensitizing or photosensitizing agents. The Cosmetic Ingredient Review (CIR) Expert Panel noted some of these ingredients may increase the penetration of other cosmetic ingredients and advised cosmetic formulators to take this into consideration. The CIR Expert Panel concluded that the toxic effects of these ingredients are observed at doses higher than would be available from cosmetics. A concentration limitation of 0.5% was chosen to ensure the absence of a chemical leukoderma effect. For p-Cresol and Mixed Cresols (which contain p-Cresol), the Panel considered that the available data are insufficient to support the safety of these two ingredients in cosmetics. Studies that would demonstrate no chemical leukoderma at concentrations of use of p-Cresol and Mixed Cresols, or would demonstrate a dose response from which a safe concentration could be derived, are needed.

Economic impact of extended-release tolterodine versus immediate- and extended-release oxybutynin among commercially insured persons with overactive bladder.

OBJECTIVE: To examine levels of persistence and compliance as well as the economic impact of extended-release tolterodine (tolterodine ER) versus immediate- and extended-release oxybutynin (oxybutynin IR or oxybutynin ER) among commercially-insured patients with overactive bladder (OAB). METHODS: Patients with OAB who initiated tolterodine ER, oxybutynin IR, or oxybutynin ER between January 2001 and December 2002 were identified from the PharMetrics Patient-Centric database; the first medication used in this timeframe was used for treatment group assignment (ie, patients were only in 1 group). Exploratory assessment of persistency and compliance was conducted among all treated patients: subjects were matched 1:1 based on the estimated propensity score for tolterodine ER in remaining analyses. Measures included patient characteristics as well as levels of medication, outpatient and inpatient resource utilization, and costs. Primary comparisons were made descriptively; costs were evaluated using generalized linear models with a gamma distribution and log-link function. RESULTS: Compliance did not differ between tolterodine ER (77.4%) and oxybutynin ER (74.3%), but was lower for oxybutynin IR (60.9%). Mean (+/- standard deviation) duration of therapy was higher for tolterodine ER (139 +/- 132 days) versus oxybutynin ER (115 +/- 122) and oxybutynin IR (60 +/- 85). Totals of 7257 and 5936 matched pairs were available for tolterodine ER versus oxybutynin ER and oxybutynin IR comparisons, respectively. The mean age was 54 years in all groups; the majority was women. Utilization of outpatient and inpatient medical services was consistently lower among tolterodine ER patients in both comparisons. Total costs were slightly lower for tolterodine ER versus oxybutynin ER (dollar 8303 +/- dollar 18 802 vs dollar 8862 +/- dollar 18 684) and oxybutynin IR (dollar 9975 +/- dollar 24860 vs dollar 10521 +/- dollar 22 602); differences were significant after multivariate adjustment. CONCLUSIONS: Use of tolterodine ER results in comparable compliance to oxybutynin ER and longer duration of use relative to either form of oxybutynin. In addition, tolterodine ER may be cost-effective relative to oxybutynin IR or oxybutynin ER among commercially-insured persons with OAB.

Treatment of overactive bladder: a model comparing extended-release formulations of tolterodine and oxybutynin.

OBJECTIVE: The objective of this study was to compare 1-year total healthcare costs for patients with overactive bladder (OAB) initiating treatment with extended-release formulations of tolterodine and oxybutynin: tolterodine tartrate extended-release capsules (tolterodine ER) versus extended-release oxybutynin chloride (oxybutynin ER). METHODS: A model was developed from the payer perspective using data from the PharMetrics Patient-Centric database. Monthly discontinuation rates were derived from a cohort of newly treated patients with OAB (tolterodine ER, n = 15 394 or oxybutynin ER, n = 7934). All were assumed to be receiving therapy for at least 1 month. Medical management costs were based on reimbursement for all services for a matched cohort of patients taking tolterodine ER and oxybutynin ER. Medical management costs for those discontinuing therapy were based on patients receiving OAB care without pharmacotherapy (n = 29 992). Drug costs were from AnalySource (December 2004). RESULTS: After the 11-month follow-up period, 21% of patients taking tolterodine ER and 15% of patients taking oxybutynin ER remained on original therapy. One-year average total costs per patient for those started on tolterodine ER were dollar 8876 and dollar 9080 for oxybutynin ER, a difference of dollar 204 per year. Sensitivity analyses indicated results were robust to changes in drug cost and probability of discontinuation. When discontinuation rates were held equal, cost differences continued to favor tolterodine ER (21%, dollar 272/yr; 15%, dollar 233/yr). CONCLUSION: Those taking tolterodine ER had lower monthly drug and medical management costs. This resulted in a total average annual cost savings of dollar 204 per patient for those started on tolterodine ER. At the end of 1 year, patients with OAB were more likely to remain on original drug treatment taking tolterodine ER versus oxybutynin ER.

Cost-effectiveness analysis of extended-release formulations of oxybutynin and tolterodine for the management of urge incontinence.

INTRODUCTION: Oxybutynin and tolterodine are two drugs widely used for the management of overactive bladder and urge urinary incontinence. The once-daily, extended-release formulations benefit from being well tolerated and efficacious. However, their costs, compared with generic immediate-release (IR) oxybutynin, are significantly greater. This study compared the cost effectiveness of oxybutynin extended-release (Oxy-XL), tolterodine extended-release (Tol-ER), tolterodine immediate-release (Tol-IR) and oxybutynin immediate-release (Oxy-IR). STUDY DESIGN: A cost-effectiveness model. METHODS: A systematic review that identified appropriate randomised clinical trials provided evidence on efficacy. Empirical models of drug effects (number of incontinent-free weeks) and persistence (proportion of patients still on therapy) were constructed in order to determine clinical effectiveness which was combined with cost data (direct medical costs to the UK NHS, year 2001 values) to calculate the drugs' cost-effectiveness from the perspective of the NHS. Univariate sensitivity analyses were conducted to test the robustness of the results. PATIENTS: Hypothetical cohort of patients with urge incontinence associated with overactive bladder. MAIN OUTCOME MEASURES AND RESULTS: The incremental cost per incontinent-free week for Oxy-IR (versus no treatment) ranged from pound sterling 2.58 to pound sterling 16.59. Oxy-XL and Tol-ER were more effective than Oxy-IR but at additional costs per incontinent-free week. Tol-IR did not appear to be a cost-effective option as it was less effective and more costly than the extended-release formulations. Uncertainty surrounding the health and cost consequences of early discontinuation affected these results, although the model results were robust to parameter uncertainty. CONCLUSION: Oxy-IR, Oxy-XL and Tol-ER appear to be cost-effective options for the management of urge incontinence from the NHS perspective. A decision among the treatments depends on the acceptable cost per additional incontinent-free week.

Canadian economic comparison of extended-release oxybutynin and immediate-release tolterodine in the treatment of overactive bladder.

BACKGROUND: Overactive bladder (OAB) is a condition characterized by urgency, increased frequency of micturition, or urge incontinence. It affects a considerable segment of the population, particularly with increasing age. Pharmacotherapy is one of the most common approaches to the treatment of OAB. OBJECTIVE: This article describes the development and results of a model comparing health-economic outcomes for the new extended-release (XL) formulation of oxybutynin and immediate-release (IR) tolterodine in a population of community-dwelling Canadian adults with OAB. METHODS: A Markov model was developed to compare health-economic outcomes over the course of 1 year. Effectiveness and treatment-persistence data were derived from the OBJECT (Overactive Bladder: Judging Effective Control and Treatment) trial, a 3-month comparison of oxybutynin XL 10 mg and tolterodine IR 4 mg, and were used, together with data from the literature (identified through a MEDLINE search of articles published between 1990 and 2003), to project outcomes beyond the trial period. Severity-specific cost profiles for incontinence were developed. In the principal analyses, cost items were limited to drug therapy, physician visits, use of pads or other protection, and laundry costs. Costs are reported in 2002 Canadian dollars. RESULTS: Costs after 1 year were estimated to be an average of $32 less per patient for oxybutynin XL compared with tolterodine IR, and 3.1 additional patients in every 100 who received oxybutynin XL were expected to attain complete continence compared with those who received tolterodine. During the course of 1 year, patients receiving oxybutynin XL were expected to have a mean 16.5 additional incontinence-free days compared with those receiving tolterodine IR. The results were sensitive to relative drug prices. In the other sensitivity analyses, however, oxybutyrin XL maintained its advantage over a wide range of inputs. CONCLUSION: The results of these analyses suggest that when priced equivalently, oxybutynin XL would reduce costs and provide better results than tolterodine IR over 1 year of treatment.

Assessment and conservative management of the neuropathic bladder.

The etiologies and forms of congenital neuropathic bladder are described: contractile (25%), acontractile (15%), and intermediate (60%). The terminology relating to neuropathic bladder is defined and the principles of bladder management are highlighted: (1) must achieve a bladder that can fill at low pressure, (2) must achieve a bladder that can store urine at low pressure, (3) must achieve sphincter resistance that is sufficient to allow urine storage, and (4) must put in place a mechanism of achieving complete voluntary bladder emptying. The approach to investigation is set out in a logical sequence, and the methods of achieving the goals highlighted above are described. All of this is put in the context of managing the handicapped patient as a whole. It also is stressed that the aim is not just to achieve continence but perhaps even more importantly to protect renal function.

A pharmacoeconomic evaluation of two new products for the treatment of overactive bladder.

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.