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Hartmann KE, McPheeters ML, Biller DH, et al. Treatment of Overactive Bladder in Women. Rockville (MD): Agency for Healthcare Research and Quality (US); 2009 Aug. (Evidence Reports/Technology Assessments, No. 187.)

  • This publication is provided for historical reference only and the information may be out of date.

This publication is provided for historical reference only and the information may be out of date.

Executive Summary

Introduction

Importance of Overactive Bladder Treatment

At minimum, 11 to 16 million women in the United States cope on a daily basis with symptoms that include sudden strong urges to urinate, difficulty delaying voids, frequent trips to the bathroom, and in many cases involuntary loss of urine when urgency strikes.1–4 They may wear pads for accidents, plan ahead for access to bathrooms, and modify their social and work lives to accommodate their symptoms. Some are very distressed by the symptoms whether mild or severe, and others find mechanisms to adapt, reporting little trouble with symptoms or interference with normal routines. Others report their symptoms negatively influence quality of life factors as varied as self-esteem, self-assessment of attractiveness, and sexual function. Many women believe that some amount of urinary incontinence is inevitable with aging. The majority of women with these symptoms do not talk with their health care providers concerning their bladder dysfunction, and providers may not systematically inquire. As a result, a small minority receive treatment.

Popular wisdom encourages self-management of symptoms of OAB through reduction of fluid intake, cutting back on caffeine, modifying voiding habits, and taking note of what individual factors influence severity of symptoms.

For this review, we operationally defined OAB as “idiopathic urinary urgency and frequency with or without associated urge urinary incontinence in adult females, not related to neurogenic conditions or as a result of (stress incontinence) surgery.” The report is focused on treatments that are prescribed or provided by a healthcare practitioner and have been formally investigated including:

  • Pharmacologic treatments, including prescription medications, both pills and patches
  • Surgeries and procedures, such as sacral neuromodulation and botulinum injections
  • Behavioral interventions, such as behavior modification programs and bladder training
  • Complementary and alternative medicine, such as acupuncture and reflexology

OAB management is usually individualized to address the component symptom(s) that the patient finds most bothersome. Where possible, we have tried to address treatments with respect to the primary component symptoms of OAB: urge urinary incontinence, urgency, and frequency, so that the women, their health care providers, payors, policy-makers, and others have a detailed picture of the expected outcomes of available treatments.

Key Questions

In preparing this report, we have answered the following key questions:

  • KQ1. What is the prevalence and incidence of overactive bladder as estimated in representative populations?
  • KQ2. Among women with overactive bladder, what are the short and long-term outcomes of the following treatment approaches, or combinations of treatment approaches?
    1. Pharmacologic treatments
    2. Procedural and surgical treatments
    3. Behavioral and physical therapy treatments
    4. Complementary and alternative medicine treatments
  • KQ3. Where direct comparisons have been made between or among treatment modalities of interest, which modalities achieve superior outcomes with respect to benefits, short and long-term risks, and quality of life?
  • KQ4. Are the short and long term outcomes of these treatment approaches modified by clinical presentation, physical exam findings, urodynamic findings, menopausal status, age or other factors?
  • KQ5. What are the costs associated with these treatment approaches?

Methods

Literature search. We employed multi-term search strategies to retrieve research about treatment of overactive bladder in women, including exploration of three databases: PubMed, MEDLINE®, EMBASE, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We also hand-searched the reference lists of relevant articles to identify additional studies. Controlled vocabulary terms served as the foundation of our searches in each database, complemented by additional keyword phrases to represent the myriad ways in which overactive bladder is referred to in the clinical literature. We also employed indexing terms within each of the databases to exclude undesired publication types (e.g., reviews, case reports, CME handouts) and items published in languages other than English. We excluded studies that (1) were published in languages other than English; (2) did not report information pertinent to the key questions; (3) had fewer than 50 participants [at enrollment]; (4) were not original studies; and (5) provided data only for stress or mixed urinary incontinence.

Study selection. Two reviewers separately evaluated abstracts for inclusion or exclusion. If one reviewer concluded the abstract should be included for full review of the article, it was retained. For the full article review, two reviewers read each article and decided whether it met our inclusion criteria. Discordance was resolved by third-party adjudication.

Quality assessment. The research team used a quality assessment approach that ensured capture of key points most relevant to this literature. Quality was assessed by two reviewers independently, who resolved differences through discussion, review of the publications and coming to consensus with the team.

Data extraction. All team members shared the task of entering information into the evidence tables. After initial data extraction, another member of the team reviewed the article and checked all table entries for accuracy, completeness, and consistency. The two abstractors reconciled disagreements concerning the information reported in the evidence tables.

Evidence synthesis. The information included in tables reflects those outcomes most consistently reported in the literature: urge incontinence episodes and number of voids per day. (Studies with weekly or other metrics that could be converted to daily metric are included.) When common measures were available across studies using roughly comparable assessments (i.e., index questions, time intervals, etc.), we compiled tables to summarize outcomes of treatments. Measures of quality of life, interference with daily activities, degree of distress from symptoms, and satisfaction with the outcomes of treatment were also common and helpful metrics in this literature.

For behavioral, surgical, and complementary and alternative treatments, we produced evidence tables, summary tables of common outcomes where possible, and provided analysis in text form. For pharmacologic treatment, we produced similar summary tables and conducted a limited meta-analysis.

Conduct of meta-analysis. Descriptive statistics were computed and examined for homogeneity among studies. Studies that reported weekly rates for UUI (urinary urge incontinence) episodes and voids were standardized to daily rates. When only ranges of continuous variables were reported (instead of standard deviations), we estimated the standard deviations by dividing the range by four.5 Study results were combined and summarized using two meta-analysis techniques, weighted averages and fixed effects regression models.6 Minimum variance weighted averages of the mean daily decrease in UUI and voids per arm were computed using weights that were inversely proportional to their standard errors. To borrow strength across arms, we used fixed effect regression models with robust standard errors (to account for the clustering by study), and weighted the study arms inversely proportional to their standard errors of the mean. Each arm was treated as a fixed effect, and study was not included in the model except in the sense that the clustering was addressed by the robust standard errors. Fixed effects models were also adjusted for mean age and proportion of women in each arm.

Literature search yield. As a result of the search, 2,559 non-duplicate articles were identified. Two hundred thirty-two articles were included in the review, representing one hundred seventy-nine distinct studies, with 75 articles pertaining to KQ1, 150 to KQ2, 34 to KQ3, 32 to KQ4, and 5 to KQ5. Reasons and process for exclusions are described in the full report.

Conflict of interest. We used a two-step process to describe the contribution of industry-sponsored research to the evidence base. The first step was to calculate the proportion of publications that explicitly state the source of the funding for research, and the second step was to calculate the proportion supported by industry among those that report funding source. These counts are important because several studies have shown that industry-sponsored research tends to produce results that are favorable to the drug manufacturer even when the research is conducted in academic medical centers.7–9

Results

KQ1. Prevalence and incidence of overactive bladder

Content of the literature. We identified 75 publications,2–4, 10–81 from 60 distinct study populations. Fifteen studies were conducted in United States populations; 24 in European populations; 13 Asian; and 8 in other countries. Thirty-eight of these studies (63 percent) appeared in print after the 2002 International Continence Society (ICS) revised definitions and 37 percent of these reported specifically about incidence or prevalence of OAB. One study prior to the standardized definitions used fully comparable definitions and the term “overactive bladder”. The strength of the evidence for understanding prevalence of OAB is moderate and for understanding incidence is weak.

Prevalence estimates. A total of 15 studies provided information specifically about OAB prevalence in adult women. These studies included a total of 64,528 women in 16 distinct populations. Estimates of prevalence ranged from 7.7 to 31.3 percent. Across all studies the average prevalence of OAB was 16.1 percent. Excluding the highest and lowest estimates, an estimated 15.1 percent of women meet criteria for OAB, with 8.2 percent of those surveyed, having OAB with a component of urge incontinence. Combined estimates from the two populations from the United States are similar 15.1 percent with OAB and 11.0 percent with a component of urge incontinence.

A larger number of studies (n=48) examined urge urinary incontinence as the primary prevalence estimate of interest. Twenty-eight appeared after the ICS 2002 standardization of definitions. Across populations, prevalence of urge incontinence ranged from 1.5 to 22.0 percent. Average urge incontinence prevalence was 9.7 percent in the United States, 10.6 percent in Europe, and 9.6 percent in Asia.

Incidence and resolution. Ten studies provided incidence data and two reported on resolution of symptoms. Estimates for annual incidence of OAB ranged from 2.6 to 143 cases per thousand, with higher estimates in the oldest population groups. A proportion of cases, 23 percent to 35 percent, resolve over a year’s time; however the majority of women have symptoms for years. No studies evaluated lifetime natural history.

KQ2: Outcomes of Treatment for Overactive Bladder

Pharmacologic treatment

Content of the literature. We identified 13 randomized controlled trials (RCTs) of oxybutynin for treatment of OAB. A total of 22 study arms compared oxybutynin at varied doses, formulations, and intervals. These studies included five placebo arms. Most participants were recruited from specialty populations with seven studies performed in the United States,82–88 three in Europe,89–91 and one each in Japan,92 Taiwan,93 and South Korea.94 These studies included a total of 2,575 women in treatment arms, and 383 women in the placebo arms.

For tolterodine there were 19 RCTs, including 29 drug arms and 13 placebo arms. Most were multinational studies conducted at centers in Europe, the United States, Australia, and Asia. A total of 6,564 women were in the treatment arms, with 3,109 women in the placebo arms.

Two RCTs compared fesoterodine at 4 and 8 mg to placebo for reducing symptoms of OAB and met criteria for inclusion in the systematic review.95, 96 These studies included a total of 1,017 women in the treatment arms, and a total of 518 women in the placebo arms.

Three RCTs investigated solifenacin compared to placebo for reducing symptoms of OAB.97–99 These studies included a total of 1,541 women in the solifenacin treatment arms, and a total of 638 women in the placebo arms.

Four RCTs provided data on the effectiveness of darifenacin.82, 100–102 These four studies included at total of 690 women in the darifenacin treatment arms and a total of 304 women in the placebo arms.

Five RCTs evaluated trospium for reduction of symptoms of OAB. Four trials compared trospium to placebo, and one compared trospium to oxybutynin. Four were conducted in the United States,103–106 and the fifth at multiple centers in Europe and Asia.90 These studies included a total of 1,309 women in the trospium treatment arms, and a total of 1,130 women in the placebo arms.103–106

Three studies assessed the role of oral estrogen therapy in different doses and formulations in the alleviation of OAB symptoms.107–109 All studies were performed in Europe and Scandinavia with a total of 514 women. Two were RCTs and one was a prospective cohort. After review and analysis of all 110 studies, of which four were good quality, 75 fair and 31 poor, including 68 RCTs, the strength of the evidence for managing OAB with pharmacologic treatment is weak to moderate for short term outcomes and weak for long term outcomes and harms.

Outcomes of treatment. All pharmacologic treatments were effective at improving one or more OAB symptoms when compared to placebo. Reductions ranged from 0.9 to 4.6 in incontinence episodes per day across all drug treatments and from 0.7 to 4.2 in voids per day. Study by study, extended release formulations achieved modestly better effects than immediate release, statistical significance varied. No one drug was definitively superior to others by preponderance of evidence, including more recently approved drugs. As estimated by meta-analysis, extended release forms (taken once a day) reduce UUI by 1.78 (95 percent CI: 1.61, 1.94) episodes per day, and voids by 2.24 (95 percent CI: 2.03, 2.46) per day. Immediate release forms (taken twice or more a day) reduce UUI episodes by 1.46 (95 percent CI: 1.28, 1.64) per day, and voids by 2.17 (95 percent CI: 1.81, 2.54) per day. Of note, placebo reduces UUI episodes by 1.08 (95 percent CI: 0.86, 1.30), and voids by 1.48 (95 percent CI: 1.19, 1.71) per day. Even in the context of small to moderate affect on symptoms, pharmacologic treatments were generally associated with increased quality of life and reductions in measures of impact or distress, compared to baseline and to placebo.

Table 1 below provides estimates of treatment effects for pharmacologic treatments represented by more than one trial arm. Some drugs and doses of drugs are not reported because the publications with trial arms for that treatment did not provide sufficient information to estimate variance in meta-analysis models.

Table 1. Estimates of mean reductions in incontinent episodes and voids per day.

Table 1

Estimates of mean reductions in incontinent episodes and voids per day.

Since baseline episodes of UUI per day ranged from 1.6 to 5.3, and voids per day from 7.2 to 13.7, these reductions (Table 1) reflect modest margins of benefit from baseline above placebo. Data was not consistently provided across studies to estimate the proportion of women who became symptom free.

Procedural and surgical treatment

Content of the literature. We identified 18 studies about surgical treatments and procedures for OAB. Eleven were of sacral neuromodulation, one of peripheral neuromodulation, and one of electromagnetic therapy. Three studied bladder instillation or injection of drugs; one was on bladder distention; and one about bladder transection. This literature included 13 case series studies: nine prospective110–118 and three retrospective.119–121

One study had both retrospective and prospective components.122 Given consideration of 18 studies, of which 11 were fair quality and seven poor, including five RCTs, the strength of the evidence for managing OAB with procedural and surgical treatment is weak for all aspects of understanding outcomes of care. One study was a prospective cohort that compared outcomes among participants receiving sacral neuromodulation to participants who had lead placement without activation of electrical stimulation.123 Four studies were RCTs: one looked at sacral neuromodulation versus medical therapy,124 one evaluated transcutaneous electromagnetic stimulation versus sham,125 and two evaluated instillation of a drug into the bladder versus placebo – one using oxybutynin126 and one using resiniferatoxin.127

Outcomes of treatment. Among the trials of procedures and surgery, one study demonstrated a statistically significant benefit of sacral neuromodulation over usual care for the reduction of episodes of incontinence per day (average reduction of 7.1 compared to 2.1 increase among subjects who had failed medical management).124 One trial demonstrated benefit of instillation of oxybutynin compared to sterile water in the reduction of voids per day (average reduction of 6.8 compared to 2.4)126 and another reported benefits from botulinum toxin treatment which is compatible with the findings of a recent Cochrane Collaboration literature review and meta-analysis.128

Behavioral interventions

Content of the literature. We identified nine studies that included only behavioral approaches; no two studies compared the same set of approaches. They included assessment of bladder training, multicomponent behavioral training, with or without biofeedback, pelvic muscle exercises or training, vaginal electrical stimulation, and caffeine reduction. The literature base included three retrospective case series.129–131 All three were conducted in community-based clinical settings.

One prospective cohort study compared three approaches to providing bladder training: self-administered, coaching, and cognitive strategies.132 Five studies were RCTs. One compared bladder training to a “control” condition.133 One compared bladder training to pelvic muscle exercises.134 One included three arms: pelvic floor muscle training, pelvic floor muscle training assisted with biofeedback, and vaginal electrical stimulation.93 Another compared three different approaches to multicomponent behavioral training: biofeedback, verbal feedback and self-administered.135 A last study compared bladder training to bladder training with caffeine reduction.136 After review and analysis of 29 studies, of which 14 were fair quality and 15 poor, including 17 RCTs, the strength of the evidence for managing OAB with behavioral approaches treatment is moderate to weak for short term outcomes and weak for long term outcomes and harms.

Outcomes of treatment. No two studies could be combined to produce summary data. Overall, behavioral approaches can be effective in reducing episodes of incontinence and daily voids. Multicomponent approaches are most effective, and they perform relatively equivalently to pharmacologic treatment. Generally speaking, improvements were modest, with decreases in incontinence episodes of up to 1.9 per day, and reductions in voids per day of up to about four. The addition of caffeine reduction reduced frequency, but made no difference in reduction of incontinence episodes. There is no evidence that behavioral approaches enhance the effectiveness of pharmacologic therapy for reducing episodes of incontinence or voiding, although they may improve patient satisfaction and quality of life measures.

Complementary and alternative therapies

Content of the literature. We identified three studies that used complementary and alternative medicine therapies to treat OAB: a fair quality trial of acupuncture,137 a fair quality trial of foot reflexology,138 and a poor quality prospective case series of hypnotherapy.139 There is weak to no evidence for complementary and alternative approaches to managing OAB.

Outcomes of treatment. The small trial of acupuncture has intriguing results related to decreased frequency of voiding and reduced symptoms of urgency which are associated with changes in cystometrics related to improved bladder capacity that are logical intermediates of the improvement in symptoms. Women felt they were improved as measured by scales that capture bother and quality of life. Evidence is insufficient to support definitive choice of acupuncture but offers preliminary information that promises modest improvements similar to those reported in many pharmacologic trials.

Reflexology is represented by a small trial with unmasking of participants that could have biased the results. No evidence supports choice of this modality. Likewise, hypnotherapy is not supported by the scant information provided by one case series with little detail, patient reported outcomes, or statistical assessment. Given the scope of placebo effects demonstrated in other well-conducted studies of OAB treatment, it is difficult to know whether to attribute any effect to hypnotherapy.

Conflict of interest. Changing trends in editorial standards have resulted in more complete reporting of funding source and author conflict of interest over the period in which the OAB literature was developing. Sources of funding were not reported for the majority of publications that appeared in the 1980s; and no publications in that decade reported on author conflict of interest. In the 1990s through the end of 2008, nine (56 percent) studies of procedural treatments (including sacral neuromodulation and bladder instillation or injection) reported source of funding, and six of the nine studies (67 percent) were industry sponsored. The other three were institutionally funded. Among studies of medications, 89 (77 percent) reported source of funding and among those, 82 (92 percent) were industry sponsored. Among studies that had a behavioral component, 13 (68 percent) reported on funding source and four had industry support. Author conflict of interest was poorly reported until the current decade, with fewer than half of all publications providing information. Within papers that did report conflict of interest, more than half of the authors (272 of 407) indicated that they had a financial relationship with one or more companies relevant to the research.

KQ3: Comparisons of Treatments

Comparisons between pharmacologic treatments

Content of the literature. Twelve RCTs included direct comparisons of pharmacologic approaches. Specific comparisons have been made in the literature for the following pairs of drugs to identify differences in reduction in urge urinary incontinence or voids per day:

  • Oxybutynin ER to Tolterodine ER84
  • Oxybutynin ER to Tolterodine IR83
  • Oxybutynin IR to Tolterodine IR89, 91, 94
  • Oxybutynin IR to Darifenacin82
  • Oxybutynin IR to Trospium IR90
  • Oxybutynin TDS to Tolterodine ER88
  • Tolterodine ER to Tolterodine IR140, 141
  • Tolterodine ER to Solifenacin99
  • Tolterodine ER to Fesoterodine96
  • Tolterodine IR to Solifenacin97

Outcomes of treatment. In the majority of comparisons, neither drug was reported more effective at reducing either incontinence episodes or voids per day with a few exceptions. Both oxybutynin and tolterodine in their extended release forms demonstrated superiority in reducing urge incontinence episodes over tolterodine immediate release.83, 140, 142 Oxybutynin extended release was more effective at reducing voids per day than tolterodine in immediate83 or extended release formulations.84

Comparisons between procedural and pharmaceutical treatments

Content of the literature. One RCT compared sacral neuromodulation to medical therapy. In this study, 98 participants were randomized to immediate sacral nerve stimulation or delayed sacral nerve stimulation. The delay group continued unspecified medical management for a six month period before having the procedure.

Outcomes of treatment. This study, which randomized after successful test stimulation, found a reduction in daily urge incontinence episodes from 9.7 to 2.6 in the sacral neuromodulation group, compared to an increase of 9.3 to 11.3 in the medical management group at 6 months (p<0.01) for patients with refractory OAB.124 At 18 months, 76 percent of participants receiving sacral neuromodulation reported that they were completely dry or had experienced a reduction in symptoms of 50 percent or greater. Note that the comparison is not ideal, as subjects continuing to receive medical therapy had already failed medical management.

Comparisons between behavioral and pharmacologic treatments

Content of the literature. Seven studies (nine papers) included behavioral and pharmacologic arms in direct comparisons.93, 143–150 This literature included one prospective cohort study,147 and six RCTs.93, 143–146, 148–150

The behavioral approaches examined included bladder training,151, 146–150 multicomponent behavioral approaches,143–145 and electrical stimulation.93

One study reported significantly greater reductions in incontinence episodes with multicomponent behavioral modification compared to oxybutynin,143 but no studies found a difference in reductions in voids per day. In the same study that found greater reductions in incontinence with behavioral treatment, participants reported higher satisfaction with behavioral compared to pharmacologic interventions.

Comparison of combined behavioral and pharmacologic treatment to pharmacologic alone

Content of the literature. Six studies examined the effect of adding a behavioral intervention to drug compared to drug alone.150–155 In all but one study, the drug was tolterodine.The literature included five RCTs150–152, 154, 155 and one randomized open-label trial.153

Outcomes of treatment. No added benefit for reducing incontinence episodes or voids per day was found by adding behavioral treatments to pharmacologic approaches for reduction in incontinence. Two studies associated the addition of behavioral modification with reductions in voids per day, but two reported no difference.

KQ4: Modifiers of Treatments

Age. Eight publications examined the relationship of age to response to pharmacologic treatment.83, 102, 156–161 Tolterodine was the focus of four of these studies;156–158, 160 and one compared oxybutynin to tolterodine.83 The largest study of tolterodine using clinically adjusted doses, was from an open-label clinical cohort of 2,250 patients from 462 urology practices in Germany. Participants on average were taking 2 mg per day and age did not predict response.157 No studies reported lack of efficacy for reducing UUI, voids per day, or symptom distress among older participants. While effect was in some cases reduced, it was not the case that age predicted worse treatment response. Older individuals do benefit from treatment.

Prior treatment. Eight publications investigated whether prior treatment with antimuscarinics predicted treatment response.85, 86, 102, 162–165 In two placebo-controlled trials of oxybutynin transdermal system85 and tolterodine IR,162 participants who had previously been on medication for OAB had comparable outcomes to those who were treatment naïve. The tolterodine study specifically commented on prior treatment failures, noting improvements among those who had failed prior treatments that were above placebo but not statistically significant; few participants were in this category making conclusions difficult to reach.162

Baseline severity. Two studies contrasted those with UUI at baseline to those without. In an open-label study of 3,824 participants with nine months of treatment, urgency, frequency, nocturia, and OAB scales were similarly improved regardless of UUI baseline status.166 In the other, open-label, study of solifenacin, with the exception of nocturia, the point estimates for improvement in individual OAB indicators were better in the group with UUI at baseline though not in each instance statistically significantly better than among those without UUI.167

Severity of UUI, grouped as severe for those with 21 or more episodes per week, did not prevent tolterodine from having an effect above placebo, and both severe and non-severe groups had a high percentage reduction in incontinence episodes per day: a decrease of 67.6 percent among those with severe UUI and 71.4 percent among those with mild to moderate UUI.168 In another study, those with severe baseline symptoms were less likely than others be symptom free at 12 weeks.157 Cure rates were reported to be comparable when comparing participants with UUI to those with MUI.169

Urodynamic findings. Five publications related baseline urodynamic findings to outcomes of treatment.89, 170–173 Three did not identify urodynamic findings that predicted poor response or non-response to treatment. Both women with and without detrusor instability had comparable benefits from treatment.171 Classification of participants as having detrusor overactivity or sensory urgency based on urodynamics was not statistically significant as an effect modifier or predictor of treatment outcomes.170 The third study to group participants by urodynamic findings had group sizes (n = 6, 25, 36, 40) too small to make definitive assessments but suggested in the two larger groups that those with low volume and high pressure profiles had comparable results to those with low volume and low pressure profiles. Among women with proven detrusor instability, those with detrusor activity in response to provocations like washing hands or running water, were less likely to improve,172 and women who reported coital incontinence were more likely to be non-responders to treatment.173

Urodynamic findings. Five publications related baseline urodynamic findings to outcomes of treatment.17, 98–101 Three did not identify urodynamic findings that predicted poor response or non-response to treatment. Both women with and without detrusor instability had comparable benefits from treatment.99 Classification of participants as having detrusor overactivity or sensory urgency based on urodynamics was not statistically significant as an effect modifier or predictor of treatment outcomes.98 The third study to group participants by urodynamic findings had group sizes (n = 6, 25, 36, 40) too small to make definitive assessments but suggested in the two larger groups that those with low volume and high pressure profiles had comparable results to those with low volume and low pressure profiles. Among women with proven detrusor instability, those with detrusor activity in response to provocations like washing hands or running water, were less likely to improve,100 and women who reported coital incontinence were more likely to be non-responders to treatment.101

BMI. A single trial of tolterodine ER, tolterodine IR, and placebo (n=1,235) reported that women who were above the mean for BMI (> 27kg/m2) were more likely to have UUI at baseline but achieved comparable results after 12 weeks of treatment.

Gender. Authors frequently reported that men, especially older men, fared less well in resolution of symptoms of OAB.85, 106, 156, 157, 174 This evidence review was focused on outcomes of treatment among women. However, in order to retain landmark studies we included a number of studies that enrolled men as long as the proportion of women in the study was 75 percent or more. This means that treatment effects may be attenuated when men are included.

KQ5: Costs of Treatments

Content of the literature .We identified five studies on financial costs related to OAB that met criteria for inclusion.175–179 All studies included assessment of direct medical costs, and two included costs due to lost productivity. One study additionally assessed financial implications for pain and suffering.

Costs of treatment. Total direct health care costs for women with OAB in 2000 were estimated at $6.9 billion, of which $1.1 billion were for pharmacologic treatment and $550 million for surgical treatment. The rest was estimated for “consequences” costs, which would include things like falls, longer hospital length of stay and skin conditions. Medication costs for OAB with the two most commonly used drugs (oxybutynin and tolterodine) ranged from $56 to $360 over a twelve month period for newly diagnosed patients. However, total health care costs were highest for patients who take oxybutynin, relative to tolterodine in any formulation, with costs lowest for patients on tolterodine ER. Explanations for this were not apparent.

Discussion

The study of OAB as a syndrome is entering its second decade. As is typical of advancing areas of research, publications based on case series are giving way to observational cohorts. Trials, beyond those required for FDA approval of indication for OAB, are appearing in the literature and health services researchers are investigating population-level factors such as cost of care and risk of rare but serious side effects of treatments.

The 2002 ICS standardization of terminology180 was associated with a productive trend toward greater attention to and clarity of operational definitions in research. Documentation of inclusion and exclusion criteria, baseline characteristics, and change in symptom profiles have become more detailed and nuanced in the last five to seven years. Improved clarity about research definitions for conducting the study and analyzing data was the case even when authors departed from ICS definitions. Simultaneously important research gains have been made in crafting, refining, and validating questionnaire and interview instruments for classifying symptoms, assessing severity of symptoms, describing impact of OAB on quality of life, and measuring satisfaction with outcomes. Despite this momentum the overall content of the current literature is fair to poor with a preponderance of study designs that do not provide strong evidence.

We find a concerning lack of high-quality evidence to inform clinical decision-making for millions of women in the United States. Medications can provide symptom relief which is often not complete, but valued by women who struggle with OAB. Well-conducted trials of greater duration and sophistication, separate from drug development and marketing efforts, are crucial. Because benefits of current treatments are modest, opportunities exist to study how to gain synergy from combinations of types of treatments. We must note that lack of evidence of benefits is not equivalent to evidence of no benefit. A number of treatments that are potentially promising warrant continued investigation. Cross-cutting concerns about the quality of research must be addressed to achieve literature that can be meaningfully synthesized. Current literature does not permit definitive conclusions about relative benefit, harm, or costs to achieve similar results. Given how common and concerning OAB is, a priority on promoting high-quality research in the United States is imperative. Women and their care providers deserve better information to guide their choices.

Cover of Treatment of Overactive Bladder in Women
Treatment of Overactive Bladder in Women.
Evidence Reports/Technology Assessments, No. 187.
Hartmann KE, McPheeters ML, Biller DH, et al.

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