The Effects of Antimuscarinic Treatments in Overactive Bladder: A Systematic Review and Meta-Analysis

Anticholinergic drugs versus placebo for overactive bladder syndrome in adults

BACKGROUND

Around 16% of adults have symptoms of overactive bladder (urgency with frequency and/or urge incontinence). The prevalence increases with age. Anticholinergic drugs are commonly used to treat this condition.

OBJECTIVES

To determine the effects of anticholinergic drugs for the treatment of overactive bladder syndrome.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Trials Register (searched 14 June 2005) and the reference lists of relevant articles.

SELECTION CRITERIA

Randomised or quasi-randomised trials in adults with overactive bladder syndrome that compared an anticholinergic drug with placebo treatment or no treatment.

DATA COLLECTION AND ANALYSIS

Two reviewer authors independently assessed eligibility, trial quality and extracted data. Data were processed as described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2005).

MAIN RESULTS

Sixty -one trials, 42 with parallel-group designs and 19 crossover trials were included (11,956 adults). Most trials were described as double-blind but were variable in other aspects of quality. The crossover trials did not present data in a way that allowed inclusion in the meta-analysis. Nine medications were tested: darifenacin; emepronium bromide or carrageenate; oxybutynin; propiverine; propantheline; tolterodine; trospium chloride; and solifenacin. One trial included the newer, slow release formulation of tolterodine. At the end of the treatment period, cure or improvement (relative risk (RR) 1.39, 95% CI 1.28 to 1.51), difference in leakage episodes in 24 hours (weighted mean difference (WMD) -0.54; 95% CI -0.67 to -0.41) and difference in number of voids in 24 hours (WMD -0.69; 95% CI -0.84 to -0.54) were statistically significant favouring medication. Statistically significant but modest sized improvements in quality of life scores were reported in recently completed trials. There was three times the rate of dry mouth in the medication group (RR 3.00 95% CI 2.70 to 3.34) but no statistically significant difference in withdrawal (RR 1.11, 95% CI 0.91 to 1.36). Sensitivity analysis, while limited by small numbers of trials, showed little likelihood that the effects were modified by age, sex, diagnosis, or choice of drug.

AUTHORS' CONCLUSIONS

The use of anticholinergic drugs by people with overactive bladder syndrome results in statistically significant improvements in symptoms. Recent trials suggest that this is associated with modest improvement in quality of life. Dry mouth is a common side effect of therapy but did not seem to have an effect on the numbers of withdrawals. It is not clear whether any benefits are sustained during long-term treatment or after treatment stops.

Treatment of the overactive bladder syndrome with muscarinic receptor antagonists - a matter of metabolites?

Antagonists of muscarinic acetylcholine receptors, such as darifenacin, oxybutynin, propiverine, solifenacin, tolterodine, and trospium, are the mainstay of the treatment of the overactive bladder syndrome. Fesoterodine is a newer drug awaiting regulatory approval. We briefly review the pharmacological activity of their metabolites and discuss how active metabolites may contribute to their efficacy and tolerability in vivo. Except for trospium, and perhaps solifenacin, all of the above drugs form active metabolites, and their presence and activity need to be taken into consideration when elucidating relationships between pharmacokinetics and pharmacodynamics of these drugs. Moreover, the ratios between parent compounds and metabolites may differ depending on genotype of the metabolizing enzymes, concomitant medication, and/or drug formulation. Differential generation of active metabolites of darifenacin or tolterodine are unlikely to influence the overall clinical profile of these drugs in a major way because the active metabolites exhibit a similar pharmacological profile as the parent compound. In contrast, metabolites of oxybutynin and propiverine may behave quantitatively or even qualitatively differently from their parent compounds and this may have an impact on the overall clinical profile of these drugs. We conclude that more comprehensive studies of drug metabolites are required for an improved understanding of their clinical effects.

The Placebo Effect in the Pharmacologic Treatment of Patients with Lower Urinary Tract Symptoms

OBJECTIVES

We reviewed placebo responses in randomised controlled trials (RCTs) for pharmacologic treatment of lower urinary tract symptoms (LUTS), including urinary incontinence (UI), overactive bladder, and benign prostatic hyperplasia. Review papers on placebo effects in non-urologic disorders were assessed to compare the magnitude of placebo responses in drugs for LUTS with those reported for other diseases.

METHODS

Data were retrieved from registration trials for LUTS drugs on the Web sites of the Food and Drugs Administration and the European Medicines Agency. Reviews were retrieved from Medline using the MeSH term "placebo effect" (English language; published between 1990 and 2005).

RESULTS

Placebo treatment of LUTS yields reductions in incontinence episodes (IEs) ranging from 32% to 65%, whereas prostate or UI symptom scores are reduced by 9-34%. Genuine drugs decrease IEs by 45-77% and symptom scores by 22-45%. Placebo responses are much lower when objective changes in voided volume or peak flow rate are assessed.

CONCLUSIONS

The placebo effect in LUTS has a strong behavioural component as patients become aware of their voiding habits and potential risk factors. Symptom severity, treatment naivety, study duration, and interaction with health care providers may also influence it. Proper patient selection, study duration, and objective and subjective outcome measures may better separate genuine treatment effects from artefacts. Observational studies with patients representative for real-life situations and covering a sufficient period of time could allow for better understanding of RCT results and their applicability in clinical practice.

Assessment of treatment outcomes in patients with overactive bladder: importance of objective and subjective measures

Overactive bladder (OAB) is a highly prevalent symptom syndrome that negatively affects health-related quality of life (HRQL). In clinical practice, the diagnosis and treatment of OAB are largely driven by a patient's reporting of symptoms, often in combination with objective assessment. Thus, OAB provides the opportunity to examine the relations between objective (eg, urodynamic studies, bladder diary variables) and subjective (eg, symptom bother, HRQL) outcomes. We compared objective and subjective results from 27 trials recently evaluated in a systematic review and meta-analysis of antimuscarinic agents used to treat OAB. Many studies demonstrated concurrent improvements in both types of outcomes. However, several reports showed that although pharmacotherapy may reduce micturition frequency or increase bladder capacity, treated patients may not perceive a significant benefit to HRQL. We conclude that objective assessments can help determine the underlying causes of OAB symptoms and assess the effects of treatment, but that these results are not always predictive of subjective outcomes, which are influenced by a patient's priorities and lifestyle, and thus highly individualized. A patient's perception of treatment success should be regarded as an important measure of efficacy because a patient considers the trade-offs between symptom improvement, adverse events, and effects on daily life when assessing overall treatment benefit. We recommend that subjective measures become standard considerations in the initial evaluation and treatment of patients with OAB.

The effects of antimuscarinics on health-related quality of life in overactive bladder: A systematic review and meta-analysis

The objective of this study was to review the effects of antimuscarinic treatments on health-related quality of life (HRQL) in patients with overactive bladder (OAB). MEDLINE, EMBASE, the Cochrane Controlled Trials Register, and the Cumulative Index to Nursing and Allied Health Literature databases were searched from 1966 through August 2004 for randomized controlled trials of antimuscarinic agents. HRQL data from included trials were extracted, and meta-analysis was performed where possible. Of 56 trials included, 25 (45%) reported HRQL and/or patient-reported outcomes. The most commonly used instruments were the Incontinence Impact Questionnaire (3 trials), the King's Health Questionnaire (KHQ; 5 trials), the Medical Outcomes Study Short Form-36 (2 trials), the Gaudenz Appraisal Questionnaire (3 trials), and the Urogenital Distress Inventory (2 trials). Results from the meta-analyses of placebo-controlled trials showed statistically significant differences in favor of antimuscarinic therapy. Differences in HRQL as assessed using the KHQ were also clinically meaningful. The meta-analysis results of active-controlled trials did not show significant differences among antimuscarinic agents. This review provides evidence that antimuscarinics provide an HRQL benefit to patients with OAB. HRQL outcomes using validated instruments are recommended for inclusion in active-controlled trials, and agreement on the most appropriate HRQL instrument is now required.

Rho kinase: a target for treating urinary bladder dysfunction?

Urinary incontinence and other urinary storage symptoms are frequent in the general population but available treatments have limited efficacy and tolerability. Rho kinase (ROCK) has a central role in the regulation of smooth muscle contraction, including that of the urinary bladder. Recent experimental evidence indicates that this role could be deregulated and exacerbated in local and systemic pathological conditions that affect the bladder. In vitro studies with prototypical ROCK inhibitors such as Y27632 and in vivo data from animal models indicate that such drugs have potential as future treatments for bladder dysfunction.

Urinary incontinence: economic burden and new choices in pharmaceutical treatment

In the year 2000, an estimated 17 million community-dwelling adults in the United States had daily urinary incontinence (UI), and an additional 33 million suffered from the overlapping condition, overactive bladder. Estimates of the total annual cost of these conditions range up to 32 billion US dollar; the largest components are management costs and the expenses associated with nursing home admissions attributable to UI. In most cases, patients with UI can be treated with pharmaceutical agents, in addition to behavioral therapy. Until recently, pharmaceutical therapy for UI has been limited, especially because the adverse effects of available agents resulted in poor adherence to treatment regimens. Recent innovations in molecular design and new dosage forms of UI medications offer the promise of fewer and less severe adverse effects and, thus, better treatment outcomes for patients. Additionally, the availability of multiple agents within a therapeutic class offers health care providers a spectrum of choices with which to personalize treatment for each individual patient. New pharmacologic treatment options for UI have the potential to allow greater independence for older persons who reside at home and to delay or avoid the costs of admission to long-term care facilities. Alternate dosage forms, which include patches and sustained-release formulations, may benefit patients who have difficulty chewing, swallowing, or remembering to take medications. Although these newer products are generally more expensive than older forms of therapy, they typically have more favorable cost-effectiveness ratios. Access to these new medications for patients enrolled in public and private health care plans may help to reduce the economic and social burden of UI care.

Orale Anticholinergika bei überaktiver Blase

Behavioural therapy and anticholinergics are the mainstays in the treatment of symptoms of overactive bladder in patients with idiopathic and neurogenic detrusor overactivity; they are the first-line treatment. Oxybutynin, propiverine, tolterodine and trospium chloride as well as the "newcomers" solifenacin and darifenacin are comparable in regards to their efficacy. However, based on different pharmacokinetics and pharmacodynamics with different resorption velocity, different metabolisation and different CNS penetration, the profile of adverse events is different, qualitatively and quantitatively. Substances that are resorbed slowly or available as slow-release formulations are tolerated better. Lipophilic anticholinergics which pass the blood-brain barrier may compromise cognitive functions, especially in geriatric patients, who are already on cholinesterase inhibitors due to memory disorders. The following article gives an overview of the anticholinergics currently prescribed in patients with symptoms of overactive bladder with special attention to the influence of pharmacokinetics/pharmacodynamics on the adverse events profile including possible CNS side effects.

Anticholinergika bei überaktiver Blase

Anticholinergics act in the treatment of overactive bladder by blocking muscarinic receptors of which five subtypes exist. Their desired effects occur via M(3) receptors, but a role for M(2) receptors is being discussed. Adverse effects such as dry mouth and constipation occur also via M(3) receptors, but M(2) and M(1) receptors can mediate side effects in the heart or on cognitive function, respectively. Therefore, an M(3)-selective drug such as darifenacin could theoretically be less effective but also have fewer cardiac or central nervous side effects. However, the limited available clinical data do not support a smaller efficacy or better general tolerability. The lack of adverse effects on cognitive function is well documented for darifenacin, but it cannot yet be determined definitively whether this discriminates it from other modern anticholinergics.

Symptom-specific efficacy of tolterodine extended release in patients with overactive bladder: the IMPACT trial

We evaluated the efficacy of tolterodine extended release (ER) for patients' most bothersome overactive bladder (OAB) symptom in a primary care setting. Patients with OAB symptoms for >or=3 months received tolterodine ER (4 mg q.d.) for 12 weeks. Among incontinent patients (n = 772), the most bothersome OAB symptoms were daytime frequency (28%), urgency urinary incontinence (UUI; 27%), nocturnal frequency (26%) and urgency (19%); among continent patients (n = 91), they were daytime frequency (47%), nocturnal frequency (42%) and urgency (10%). Sixty-nine per cent of patients had one or more comorbid conditions. By week 12, there were significant reductions in patients' most bothersome symptom: -80% for UUI, -78% for urgency episodes, -40% for nocturnal frequency and -30% for daytime frequency (p < 0.0001). The most common adverse events were dry mouth (10%) and constipation (4%). In primary care practice, bothersome OAB symptoms can be effectively and safely treated with tolterodine ER, even in patients with comorbid conditions.

A Shifted Paradigm for the Further Understanding, Evaluation, and Treatment of Lower Urinary Tract Symptoms in Men: Focus on the Bladder

Lower urinary tract symptoms (LUTS) are highly prevalent among older men and have a negative impact on health-related quality of life. Frequent comorbidity with potential prostatic disease adds complexity to the management of male LUTS. In this review, we discuss the pathophysiological conditions that underlie male LUTS, and examine the relationship between symptoms and urodynamic findings. The contribution of bladder dysfunction to male LUTS, with a particular emphasis on overactive bladder (OAB) symptoms, is explored. We also consider pharmacotherapeutic options for male LUTS. Pharmacotherapies that target the prostate (alpha1-receptor antagonists and 5alpha-reductase inhibitors) often fail to alleviate OAB symptoms, and may not be the most appropriate therapy for men with storage LUTS. Multiple studies have suggested that antimuscarinic therapy alone or in combination with alpha1-receptor antagonists improve OAB symptoms in men with and without bladder outlet obstruction. Although these agents may represent appropriate first-line therapies for men with OAB symptoms, the therapeutic potential of antimuscarinics alone or in combination with alpha1-receptor antagonists in this population should be evaluated in large-scale, well-designed clinical trials.

Cost implications of antimuscarinic drugs in the treatment of overactive bladder syndrome

Overactive bladder syndrome is highly prevalent, particularly among the elderly. As well as the consequent morbidity, such as urinary infections, skin irritation and bone fractures, almost all aspects of quality of life, personal and social, are influenced. Therefore, the associated cost is substantial. Pharmacotherapy with antimuscarinics is the mainstay of treatment. Because of the good balance between efficacy, safety and tolerability, these drugs seem to be cost-effective therapeutic modalities for overactive bladder. In the milieu of a constantly ageing population, rising demand for the treatment of health conditions and the need for rational use of healthcare resources, further studies with long-term antimuscarinic drug treatment and follow-up are needed to redefine their therapeutic value.

The Causes and Consequences of Overactive Bladder

Overactive bladder (OAB) is a syndrome characterized by symptoms of urinary urgency with or without urgency urinary incontinence (UUI), usually with frequency and nocturia. OAB affects approximately 17% of women in the United States and Europe. The causes of OAB, as with many bladder disorders, are multifactorial and are not completely understood. The primary functions of the lower urinary tract (bladder and bladder outlet mechanism) are storage and evacuation of urine. The bladder and the micturition cycle are under complex neural control involving both the sympathetic and parasympathetic nervous systems. Micturition may occur in response to the activation of receptors in the bladder muscle and detection of chemical stimuli by receptors within the bladder lining. Neurogenic or myogenic bladder dysfunction can lead to the symptoms of urgency, frequency, and UUI that characterize OAB. The consequences of this condition are far-reaching and include direct medical consequences and coping strategies that adversely affect quality of life. Although the prevalence of OAB increases with age, it is not a normal consequence of aging. Antimuscarinic agents (e.g., oxybutynin, tolterodine, trospium, solifenacin, and darifenacin) have demonstrated efficacy for the treatment of OAB symptoms in multiple clinical trials. This review explores the physiological basis for OAB, the effects of OAB on health-related quality of life, and the pharmacotherapies that may provide relief to patients with this distressing condition.

The overactive bladder: review of current pharmacotherapy in adults. Part 1: pathophysiology and anticholinergic therapy

Overactive bladder is a syndrome characterised by urinary urgency, with or without urge incontinence, and usually with frequency and nocturia. It affects millions of people of all ages worldwide and causes significant morbidity, especially in terms of health-related quality of life. It poses a huge economic burden on health resources. Managing such patients involves a thorough history, physical examination and the use of pertinent investigations before the initiation of treatment. Therapy consists of lifestyle changes, bladder training, anticholinergics, second-line agents such as resiniferatoxin instillation or botulinum toxin injections into the bladder in refractory cases and, finally, in intractable cases, surgery. In the first part of this review of pharmacotherapy for the treatment of this condition, the focus is on the pathophysiological factors potentially involved in overactive bladder and covers the wide range of currently available first-line anticholinergic agents. Treatment algorithms are suggested on the basis of current literature.

Open-Label Study of the Safety and Pharmacokinetics of Solifenacin in Subjects With Hepatic Impairment

Determining the pharmacokinetics and safety of solifenacin succinate, a once-daily, oral antimuscarinic agent indicated for treatment of overactive bladder, in subjects with hepatic impairment. In this open-label study, 16 subjects (eight with moderate hepatic impairment [defined as a Child-Pugh score of 7 - 9], eight healthy) received a single oral 10 mg solifenacin dose. Blood and urine were collected for pharmacokinetic assessments. Pharmacokinetic parameters (primary: area under the plasma concentration-time curve from time 0 to infinity [AUC(0-infinity)] and maximum plasma concentration [C(max)]) and safety were evaluated for solifenacin and its metabolites. There were no clinically relevant differences in safety. Moderate hepatic impairment increased AUC(0-infinity) by 60%, and the mean elimination half-life of solifenacin and several of its metabolites was longer versus healthy subjects. Mean C(max) values were comparable between the groups. A single oral dose of solifenacin was well tolerated in hepatically impaired and healthy subjects; however, moderate hepatic impairment influenced solifenacin pharmacokinetics. In patients with mild hepatic impairment, solifenacin may be used without special caution; however, in patients with moderate hepatic impairment, doses greater than 5 mg are not recommended and the 5 mg dose should be used with caution.

[Overactive bladder: prospects and limitations of botulinum toxin]

Botulinum toxin is the most potent poison known to man. It is produced by Clostridium botulinum and consists of a heavy chain which is responsible for the internalization of the toxin into the cytosol and a light chain that has the ability to cleave proteins within the nerve terminal. As those proteins are essential for normal vesicular transport and fusion of acetylcholine, botulinum toxins are able to prevent its release at the presynaptic membrane, resulting in a chemodenervation of the detrusor muscle after intravesical injection of the toxin and an impressive reduction of symptoms of overactive bladder. Clinical studies show success rates between 60 and 96% for neurogenic and non-neurogenic detrusor overactivity. Thus, application of botulinum toxin to the lower urinary tract appears to be an efficient, safe and minimally invasive procedure.