Solifenacin for Overactive Bladder: Patient-Reported Outcomes from a Large Placebo-Controlled Trial

Regular and Irregular Use and Reasons for Discontinuation of Solifenacin Therapy in Patients with Overactive Bladder Managed by Urologists

Solifenacin, a selective muscarinic receptor antagonist, is one of the best-tolerated and most effective medicines that relieve storage symptoms in patients with an overactive bladder (OAB). However, the persistence of solifenacin in daily clinical practice remains far below that reported in clinical trials. This study aimed to analyze the adherence of patients to the therapy and the reasons for solifenacin discontinuation and non-regular use in OAB patients managed by urologists. Data concerning non-compliance and the discontinuation of solifenacin, along with the reasons, were collected during two consecutive visits for 64,049 OAB outpatients. Over the two visits, 81.6% of the patients continued therapy, and 88.6% were taking solifenacin regularly. An age ≥ 75 yrs., the male sex, a rural or small-city dwelling, and a prescription of ≥10 mg predicted therapy continuation. The female sex, a higher education, a short or long duration of an OAB, and a non-idiopathic OAB predicted regular use. The persistence of nycturia and urinary incontinence during therapy predicted both discontinuation and non-regular use. Dissatisfaction with therapy was the most frequent reason for discontinuation. In conclusion, an initial prescription of solifenacin at a low dose reduces the chance of OAB symptom improvement and results in more frequent discontinuation. A high rate of discontinuation related to dissatisfaction suggests unrealistic expectations for OAB patients and insufficient education by urologists.

Oral anticholinergic drugs versus placebo or no treatment for managing overactive bladder syndrome in adults

BACKGROUND

Around 16% of adults have symptoms of overactive bladder (OAB; urgency with frequency and/or urge incontinence), with prevalence increasing with age. Anticholinergic drugs are commonly used to treat this condition. This is an update of a Cochrane Review first published in 2002 and last updated in 2006.

OBJECTIVES

To assess the effects of anticholinergic drugs compared with placebo or no treatment for treating overactive bladder syndrome in adults.

SEARCH METHODS

We searched the Cochrane Incontinence Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, WHO ICTRP and handsearching of journals and conference proceedings (searched 14 January 2020), and the reference lists of relevant articles. We updated this search on 3 May 2022, but these results have not yet been fully incorporated.

SELECTION CRITERIA

We included randomised or quasi-randomised trials in adults with overactive bladder syndrome that compared an anticholinergic drug alone with placebo treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and extracted data from the included studies, including an assessment of the risk of bias. We assessed the certainty of the body of evidence using the GRADE approach. We processed data as described in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included 104 studies, 71 of which were new or updated for this version of the review. Although 12 studies did not report the number of participants, there were 47,106 people in the remainder of the included studies. The majority of the studies had insufficient information to allow judgement of risk of bias and we judged them to be unclear for all domains. Nine anticholinergic drugs were included in these studies: darifenacin; fesoterodine; imidafenacin; oxybutynin; propantheline; propiverine; solifenacin; tolterodine and trospium. No studies were found that compared anticholinergic drugs to no treatment. At the end of the treatment period, anticholinergics may slightly increase condition-specific quality of life (mean difference (MD) 4.41 lower, 95% confidence interval (CI) 5.28 lower to 3.54 lower (scale range -100 to 0); 12 studies, 6804 participants; low-certainty evidence). Anticholinergics are probably better than placebo in terms of patient perception of cure or improvement (risk ratio (RR) 1.38, 95% CI 1.15 to 1.66; 9 studies, 8457 participants; moderate-certainty evidence), and the mean number of urgency episodes per 24-hour period (MD 0.85 lower, 95% CI 1.03 lower to 0.67 lower; 23 studies, 16,875 participants; moderate-certainty evidence). Compared to placebo, anticholinergics may result in an increase in dry mouth adverse events (RR 3.50, 95% CI 3.26 to 3.75; 66 studies, 38,368 participants; low-certainty evidence), and may result in an increased risk of urinary retention (RR 3.52, 95% CI 2.04 to 6.08; 17 studies, 7862 participants; low-certainty evidence). Taking anticholinergics may be more likely to lead to participants withdrawing from the studies due to adverse events (RR 1.37, 95% CI 1.21 to 1.56; 61 studies, 36,943 participants; low-certainty evidence). However, taking anticholinergics probably reduces the mean number of micturitions per 24-hour period compared to placebo (MD 0.85 lower, 95% CI 0.98 lower to 0.73 lower; 30 studies, 19,395 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

The use of anticholinergic drugs by people with overactive bladder syndrome results in important but modest improvements in symptoms compared with placebo treatment. In addition, recent studies suggest that this is generally associated with only modest improvement in quality of life. Adverse effects were higher with all anticholinergics compared with placebo. Withdrawals due to adverse effects were also higher for all anticholinergics except tolterodine. It is not known whether any benefits of anticholinergics are sustained during long-term treatment or after treatment stops.

Prevalence and Factors Associated with Cumulative Anticholinergic Burden Among Older Long-Stay Nursing Home Residents with Overactive Bladder

BACKGROUND

Overactive bladder (OAB), the primary cause of urinary incontinence in nursing homes, is commonly treated with anticholinergic medications; however, the elderly population is vulnerable to the adverse effects associated with anticholinergic burden. Given the relatively high prevalence of OAB among nursing home residents, it is important to understand the magnitude of anticholinergic burden in this population.

OBJECTIVES

The objectives of this study were to (1) examine the prevalence of cumulative anticholinergic burden among long-stay nursing home (LSNH) residents with OAB; and (2) identify the factors associated with varying levels of cumulative anticholinergic burden.

METHODS

This was a retrospective, cohort study using Minimum Data Set-linked Medicare claims data. Anticholinergic burden was determined based on the Anticholinergic Cognitive Burden scale and patient-specific dosing using defined daily dose. The Andersen Behavioral Model framework was used to identify the predisposing, enabling, and need factors associated with levels of anticholinergic burden. Multivariable logistic regression models were developed to determine the factors associated with levels of anticholinergic burden.

RESULTS

A total of 123,308 LSNH residents with OAB were identified; 87.2% had some degree of anticholinergic burden and 27.3% had high cumulative burden. Multiple factors were associated with higher levels of burden, including younger age, female sex, and non-Hispanic White ethnicity (predisposing factors); dual eligibility, Southern geographic region, and rural residence (enabling factors); and a number of comorbidities and concomitant medications (need factors).

CONCLUSIONS

This study revealed a high level of anticholinergic burden among LSNH residents. Multiple factors were associated with a high level of burden. There is a need to optimize the use of anticholinergics due to their significant safety concerns in the LSNH setting.

Nocebo Response in the Pharmacological Management of Overactive Bladder: A Systematic Review and Meta-analysis

CONTEXT

The role of a nocebo response in managing urology patients is unclear.

OBJECTIVE

To assess the nocebo response in randomized placebo-controlled overactive bladder (OAB) trials of pharmacological treatment by investigating the adverse events in the placebo arms.

EVIDENCE ACQUISITION

PubMed, Scopus, Embase, and Cochrane Central Register of Controlled Trials were searched to identify potential randomized controlled trials published from 1998 to November 2019. After evaluating the risk of bias in the selected studies, all selected full-text articles were included due to their overall acceptable quality. We extracted the event rate of the most commonly reported adverse events in the placebo arms of OAB trials, and finally, we performed a meta-analysis to calculate the cumulative rate of certain adverse events. The primary outcomes were the event rate of adverse events in the placebo arms of OAB trials of pharmacological treatment, and differences in adverse events in the placebo groups based on drug type and routes of administration.

EVIDENCE SYNTHESIS

After a systematic search and risk of bias assessment, 57 trials comprising 15 446 patients were included in this systematic review. We selected 13 commonly reported adverse events for the meta-analysis. Owing to the possible differences in study samples and design, we used a random model for the analysis. The average age of the patients was 59.5 yr and 79.8% were female. Dry mouth was the most commonly evaluated adverse event reported in 57 studies comprising 15 324 patients; the mean event rate was 4.9% (95% confidence interval [CI] 0.042-0.057, p < 0.001). Constipation was the second most commonly reported adverse event in 49 studies comprising 14 556 patients; the mean event rate of constipation was 2.6% (95% CI 0.022-0.031, p < 0.001). The event rate of headache was evaluated in 33 studies comprising 10 202 patients, with a mean event rate of 3.1% (95% CI 0.026-0.037, p < 0.001).

CONCLUSIONS

Dry mouth, constipation, headache, and nasopharyngitis were the most prevalent events in the included studies. The nocebo response plays a statistically significant role in causing and/or facilitating adverse events. Health care providers should have a better understanding of the positive and negative expectations associated with therapies to achieve the best possible outcomes for each individual patient. Finally, identification of the real effect of nocebo requires studies that also include a no-treatment arm. Research could help us better understand and potentially modify the nocebo response.

PATIENT SUMMARY

In this meta-analysis of 57 studies comprising 15 446 patients, we reviewed the adverse events extracted from the placebo arms of randomized controlled trials studying therapies for overactive bladder. Dry mouth, constipation, headache, and urinary tract infection were the most common adverse events. Adverse events varied based on the drug type and the route of administration. Negative expectations from the therapy and giving verbal information to the patient can cause/alleviate adverse events.

Assessment of Anticholinergic Use After Fading of BTX-A Effects in Refractory Idiopathic Overactive Bladder: A Prospective Blinded Randomized Trial

PURPOSE

To evaluate the efficacy and safety of re-treatment with anticholinergics on refractory idiopathic overactive bladder (OAB) previously treated with intravesical botulinum neurotoxin type A (BTX-A) injections.

METHODS

One hundred patients were initially managed by intravesical injections of 100 IU of BTX-A. After the effects of BTX-A faded, patients were randomized into 2 groups: group A patients received solifenacin (10 mg) for 12 weeks (study group), while group B patients received placebo treatment for 12 weeks (control group), then subsequently received solifenacin (10 mg) for another 6 weeks. All patients underwent preoperative urodynamic testing. Patients were asked to complete the validated overactive bladder symptoms score (OABSS) and incontinence quality of life (I-QoL) instruments after the effects of intravesical BTX-A faded and at 12 weeks of follow-up. Univariate and multivariate analyses of the factors affecting treatment response were conducted.

RESULTS

At 12 weeks of follow-up, in group A, all OABSS items, including the total score, had improved significantly (P<0.0001). Group A had lower frequency and amplitude of detrusor overactivity and detrusor leak point pressure (P<0.0001, P=0.03, and P=0.01, respectively). Cystometric capacity also increased significantly (P=0.007), as did all I-QoL parameters. In a comparison of patients with failed treatment and patients with successful treatment, female sex, repeated intravesical BTX-A injections, and increased bladder capacity were statistically significant (P=0.001, P=0.0001, and P=0.002, respectively). Repeated intravesical BTX-A injections and increased bladder capacity were independent factors predicting treatment success.

CONCLUSION

In patients with refractory idiopathic OAB, reuse of anticholinergics could be an effective treatment option in patients after the effects of BTX-A fade. Repeated intravesical BTX-A injections and increased cystometric capacity could affect treatment response.

No. 283-Treatments for Overactive Bladder: Focus on Pharmacotherapy

OBJECTIVE

To provide guidelines for pharmacotherapy to treat overactive bladder syndrome (OAB).

OPTIONS

Pharmacotherapy for OAB includes anticholinergic (antimuscarinic) drugs and vaginal estrogen. Both oral and transdermal anticholinergic preparations are available.

OUTCOMES

To provide understanding of current available evidence concerning safety and clinical efficacy of pharmacotherapy for OAB; to guide selection of anticholinergic therapy based on individual patient characteristics.

EVIDENCE

The Cochrane Library and Medline were searched for articles published from 1950 to the present related to individual anticholinergic drugs. Review articles on management of refractory OAB were also examined. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to 2010.

VALUES

The quality of evidence is rated and recommendations are made using the criteria described by the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Anticholinergics are the mainstay of pharmacotherapy for OAB. Evidence for their efficacy is mostly derived from short-term phase III randomized drug trials. Placebo response is strong, and long-term follow-up and patient subjective outcome data are lacking. Care providers need to be well acquainted with the side effects of anticholinergics and select therapy based on individual patient parameters.

RECOMMENDATIONS

A retrospective study of treatment persistence and adherence to α-blocker plus antimuscarinic combination therapies, in men with LUTS/BPH in the Netherlands

Background

To assess treatment persistence and adherence in men ≥45 years of age with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH), using prescription records from the Netherlands IMS Lifelink™ LRx database.

Methods

In this retrospective, observational cohort study, we identified men who received combination therapy with an α-blocker plus an antimuscarinic (e.g. solifenacin or tolterodine) between 1 November 2013 and 31 October 2014. Treatment could be received as a fixed-dose combination (FDC) tablet or as two drugs administered together (concomitant therapy), if both combination drugs were prescribed within 30 days. The primary objective was to assess treatment persistence, defined as the time from initiation of combination therapy until first discontinuation of the FDC or at least one of the drugs given concomitantly (i.e. ≥30 days without prescription renewal). Subgroup and sensitivity analyses were conducted to assess persistence by antimuscarinic agent, and with different gap lengths used to define discontinuation (45, 60 and 90 days), respectively.

Results

A total of 1891 men received an α-blocker plus an antimuscarinic (FDC, N = 665; concomitant therapy, N = 1226). Median time to discontinuation was significantly longer with FDC versus concomitant therapy (414 vs. 112 days; adjusted hazard ratio [HR] 2.04, 95% confidence interval 1.77, 2.35; p < 0.0001). Persistence at 12 months (51.3% vs. 29.9%) was also significantly greater with FDC compared with concomitant therapy. Assessment of antimuscarinic subgroups showed that median time to discontinuation was longest with solifenacin combinations (214 days) compared with other antimuscarinic combinations (range, 47–164 days; adjusted HR range, 1.27–1.77, p = 0.037). No observable impact on treatment persistence was found by adjusting the gaps used to define discontinuation.

Discussion

This study of real-world evidence of men with LUTS/BPH treated with α-blocker plus antimuscarinic combination therapy in the Netherlands showed that treatment persistence was significantly greater in those who received a FDC tablet compared with combination therapy given concomitantly. The study also shows that treatment persistence was extended in men who received combination therapy containing solifenacin compared with other antimuscarinics.

Conclusions

Overall, these findings may be useful for prescribers, as improved persistence on-treatment may translate into improved outcomes for men with LUTS/BPH. Further study is warranted to establish the key drivers of persistence in men receiving combination therapy for LUTS/BPH.

Electronic supplementary material

The online version of this article (doi:10.1186/s12894-017-0226-2) contains supplementary material, which is available to authorized users.

Solifenacin in Children and Adolescents with Overactive Bladder: Results of a Phase 3 Randomised Clinical Trial

BACKGROUND

Solifenacin, an effective, well-tolerated treatment for adult overactive bladder (OAB) symptoms, has not been evaluated in placebo-controlled paediatric clinical trials.

OBJECTIVES

To evaluate the efficacy and safety of once-daily oral solifenacin suspension in OAB patients aged 5-<12 yr (children) and 12-<18 yr (adolescents).

DESIGN, SETTING, AND PARTICIPANTS

The study involved a 4-wk urotherapy run-in followed by 1:1 randomisation to 12-wk double-blind solifenacin or placebo treatment alongside urotherapy.

INTERVENTION

Solifenacin paediatric equivalent doses (PEDs) of adult doses: 2.5mg, 5mg, 7.5mg, and 10mg. The starting dose was PED 5mg; all patients were titrated to an optimum dose at 3-wk intervals over 9 wk, resulting in ≥3 wk at the optimum dose before end of treatment (EoT).

OUTCOME MEASUREMENTS AND STATISTICS

Superiority of solifenacin versus placebo in change from baseline to EoT for mean volume voided/micturition (MVV, primary endpoint); daytime maximum volume voided/micturition (DMaxVV); incontinence episodes (mean/24h); mean number of incontinence-free days or nights/7 d; micturition frequency; and Micturition frequency adjusted for baseline total voided volume (VT_B) as an exploratory parameter). Efficacy parameters were analysed using analysis of covariance. Safety parameters (treatment-emergent adverse events, serious adverse events, laboratory variables, vital signs, electrocardiogram, postvoid residual volume) are summarised using descriptive statistics.

RESULTS AND LIMITATIONS

In children, solifenacin was superior to placebo in terms of the change from baseline to EoT for MVV (solifenacin-placebo difference 12.1ml, 95% confidence interval [CI] 0.2-24.0; p=0.046), DMaxVV (difference in adjusted mean change from baseline for solifenacin-placebo 31.9ml, 95% CI 4.3-59.5; p=0.024), VT_B-adjusted micturition frequency (p=0.028). Other endpoints were not significantly different. Solifenacin was well tolerated. For adolescents, it was not possible to draw firm efficacy conclusions because of the low numbers recruited.

CONCLUSIONS

Once-daily solifenacin oral suspension in children with OAB was superior to placebo for MVV (primary efficacy endpoint) and was well tolerated.

PATIENT SUMMARY

In this 12-wk study, a once-daily oral suspension of solifenacin in children aged 5-<12 yr with overactive bladder was superior to placebo in increasing mean volume voided/micturition, the primary efficacy variable in the study. Solifenacin was well tolerated, with a low incidence of dry mouth and constipation. This study is registered at ClinicalTrials.gov as NCT01565707.

Treatments for overactive bladder: focus on pharmacotherapy

OBJECTIVE

To provide guidelines for pharmacotherapy to treat overactive bladder syndrome (OAB).

OPTIONS

Pharmacotherapy for OAB includes anticholinergic (antimuscarinic) drugs and vaginal estrogen. Both oral and transdermal anticholinergic preparations are available.

OUTCOMES

To provide understanding of current available evidence concerning safety and clinical efficacy of pharmacotherapy for OAB; to guide selection of anticholinergic therapy based on individual patient characteristics.

EVIDENCE

The Cochrane Library and Medline were searched for articles published from 1950 to the present related to individual anticholinergic drugs. Review articles on management of refractory OAB were also examined. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to 2010.

VALUES

The quality of evidence is rated and recommendations are made using the criteria described by the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Anticholinergics are the mainstay of pharmacotherapy for OAB. EVIDENCE for their efficacy is mostly derived from short-term phase III randomized drug trials. Placebo response is strong, and long-term follow-up and patient subjective outcome data are lacking. Care providers need to be well acquainted with the side effects of anticholinergics and select therapy based on individual patient parameters. Recommendations 1. Behavioural management protocols and functional electrical stimulation should be offered in the spectrum of effective primary treatments for overactive bladder syndrome. (I-A) 2. Oral oxybutynin, immediate and extended release, as well as transdermal oxybutynin, may be offered as treatment for overactive bladder syndrome, as they are associated with significant objective clinical improvement at 12 weeks. (I-A) Oxybutynin immediate release has superior cost-effectiveness but more side effects than other anticholinergics. (I-A) Adverse events associated with transdermal oxybutynin are fewer than with oral oxybutynin. (I-A) 3. Tolterodine, immediate and extended release, may be offered as treatment for overactive bladder syndrome, as it is associated with significant objective clinical improvement at 12 weeks. (I-A) 4. Trospium, immediate and extended release, may be offered as treatment for overactive bladder syndrome as it is associated with significant clinical improvement at 12 weeks. (I-A) Trospium is an adequate anticholinergic choice for overactive bladder syndrome patients with pre-existing cognitive impairment (II-B) and for overactive bladder syndrome patients taking concurrent CYP450 inhibitors. (III-B) 5. Solifenacin may be offered as treatment for overactive bladder syndrome, as it is associated with significant objective clinical improvement at 12 weeks. (I-A) Solifenacin may be an adequate anticholinergic choice for elderly overactive bladder syndrome patients or patients with pre-existing cognitive dysfunction. (I-B) 6. Darifenacin may be offered as treatment for overactive bladder syndrome, as it is associated with significant objective clinical improvement at 12 weeks. (I-A) Darifenacin is an adequate anticholinergic choice for overactive bladder syndrome patients with pre-existing cardiac concerns or cognitive dysfunction. (I-B) 7. Overactive bladder syndrome patients should be offered a choice between bladder training, functional electric stimulation, and anticholinergic therapy, as there is no difference in cure rates. Combination therapy does not have a clear advantage over one therapy alone. (I-A) 8. The choice of anticholinergic therapy should be guided by individual patient comorbidities, as objective efficacy of anticholinergic drugs is similar. (I-A) Dose escalation does not improve objective parameters and causes more anticholinergic adverse effects. It is, however, associated with improved subjective outcomes. (I-A) To decrease side effects, switching to a lower dose or using an extended release formulation or a transdermal delivery mechanism should be considered. (I-A) 9. Education on treatment efficacy, realistic expectations, and length of treatment should be offered to patients upon initiation of anticholinergic therapy, as continuation rates for anticholinergic therapy are low. (III-B) 10. Oral or transdermal estrogen supplementation should not be recommended for treatment of overactive bladder syndrome as its effects are comparable to placebo. (I-E) Vaginal estrogen can be suggested for subjective improvements in overactive bladder syndrome symptoms. (III-B) 11. Intravesical botulinum toxin injection and sacral nerve and posterior tibial nerve stimulation are clinically effective options for patients with overactive bladder syndrome unresponsive to conservative options, anticholinergics, or vaginal estrogen. (I-A).

Efficacy assessments in randomized controlled studies of acute therapy for hereditary angioedema

Hereditary angioedema (HAE) is a rare disorder caused by a deficiency of C1 esterase inhibitor, characterized by recurrent, highly variable attacks of subcutaneous or submucosal edema that may affect multiple body sites. Clinical studies of acute HAE therapies have required the use of assessment tools to evaluate both pretreatment attack severity (baseline severity) and changes in symptom severity following treatment (treatment response). This article reviews the range of assessment tools used for efficacy determination of acute HAE therapies, based on a review of relevant clinical studies. Because the goal is relief of symptoms (rather than cure), patient-reported outcomes (PROs) form the basis of these tools. Tools used to evaluate baseline severity typically employ location-specific assessment of symptom severity, using either categorical descriptions (which may be converted into numerical variables) or a visual analog scale (VAS). Some studies define the initial or most symptomatic site as an "index" site for purposes of efficacy determination, while others (such as the Mean Symptom Complex Severity score used in clinical studies of ecallantide) use a composite score that reflects all sites. Assessment of treatment response typically employs the same tool(s) to evaluate baseline severity, and may be either time-based (e.g., time to achievement of minimal or no symptoms) or symptom-based (e.g., degree of symptom relief at predetermined time points). Although it is unlikely that therapies will be compared using identical assessment tools, prospective or retrospective validation ensures the adequacy and relevance of such tools, which should be taken into consideration when therapies are compared.

Solifenacin for overactive bladder: a systematic review and meta-analysis

This study aims to evaluate the efficacy and safety of solifenacin for treating overactive bladder. Randomized controlled trials (RCTs) were identified and extracted from MEDLINE, Embase, and CENTRAL. The quality of the included RCTs was assessed using the Jadad score, and heterogeneity was analyzed using the chi-squared test. The data of the included RCTs were collected, extracted, and assessed by our protocol. A total of nine RCTs were identified from the search strategy. Compared with the placebo and tolterodine treatments, both short-term (mostly 12-week) trials indicated that solifenacin significantly reduced urgency episodes, micturitions, and incontinence episodes per 24 h. Compared with the solifenacin (5 mg) group, the solifenacin (10 mg) group was significantly better in terms of the number of micturitions per 24 h. With regard to adverse effects, the patients treated with solifenacin had significantly higher rates of constipation and blurred vision than patients treated with tolterodine. The solifenacin therapy was not inferior to tolterodine in terms of efficacy profiles and had a similar incidence of overall adverse events compared with tolterodine treatment. Solifenacin (5 mg) is thus a recommended dose because of its reported balance between efficacy and acceptable tolerability.

Cost-effectiveness analysis of anti-muscarinic agents for the treatment of overactive bladder

OBJECTIVE

To determine the cost-effectiveness of pharmacologic treatments for overactive bladder (OAB) in the US.

METHODS

A decision model was constructed based on studies of effectiveness, adverse consequences, co-morbid conditions, and medical costs for the treatment of OAB. Treatment success was defined as no incontinence episodes for 3-7 days or 3-7 consecutive dry days. Estimates of treatment success were obtained from clinical trials and included darifenacin, fesoterodine, oxybutynin immediate release (IR), oxybutynin extended release (ER), oxybutynin topical gel, oxybutynin transdermal patch, solifenacin, tolterodine IR, tolterodine ER, trospium IR, and trospium ER. Probabilistic sensitivity analysis was conducted using Monte Carlo simulation.

RESULTS

A total of 51 OAB studies were identified and 11 reported treatment success. Mean continence rates varied in the literature from 21.0% with trospium IR to 51.0% with solifenacin. The 95% CI for solifenacin's success rate was statistically higher than other regimens due to the higher continence rates from the clinical trials. Oxybutynin IR and oxybutynin ER were significantly less costly than other products. The product with the lowest incremental cost-effectiveness ratio (ICER) relative to oxybutynin IR was solifenacin at $1338 (± 168) per additional continent patient. The cost-effectiveness acceptability curve indicated that oxybutynin IR was the most cost-effective regimen when willingness-to-pay values were less than $10,000 per additional continent patient. Solifenacin was most cost-effective at higher willingness-to-pay values.

CONCLUSION

There was broad overlap in effectiveness among the anti-muscarinic products, except solifenacin had a significantly higher continence rate. Oxybutynin IR and oxybutynin ER were significantly less costly than other anti-muscarinic regimens, and these two products have a useful role to play in the management of OAB. However, for patients unable to tolerate the lower cost products, formularies benefit from solifenacin among branded products since the cost-effectiveness acceptability curve demonstrated it was the product most likely to be cost-effective after oxybutynin IR.