A review of medical management of the overactive bladder syndrome

Abstract

The overactive bladder syndrome (OAB) has been defined by the International Continence Society as urinary urgency with or without urge incontinence usually with frequency and nocturia. Thus, it is a diagnosis based on lower urinary tract symptoms alone. While not life threatening, it can have a considerable adverse impact on the quality of lives of those who suffer from it, and it is highly prevalent within society. Recent epidemiological studies have reported the overall prevalence of OAB in women to be 16.9%, suggesting that there could be 17.5 million women in the USA who suffer from the condition. The prevalence increases with increasing age being 4.8% in women younger than 25 years and 30.9% in those older than 65 years. This is supported by recent prevalence data from Europe in which 16 776 interviews were conducted in a population-based survey. The overall prevalence of OAB in individuals aged 40 years or older was 16.6% and increased with increasing age. Frequency, the most common symptom, was reported by 85% of respondents, while 54% complained of urgency and 36% of urge incontinence. When considering management, 60% had consulted a physician, although only 27% were currently receiving treatment. Initial management of OAB should take into account the individuals’ lifestyle and any appropriate interventions that can be employed to minimise symptoms. For example, reducing excessive fluid intake and minimising caffeine and alcohol consumption may be helpful, as well as reviewing any medication that may have an impact on lower urinary tract function, such as diuretics. Behavioural therapies and, in particular, bladder retraining may help a person regain central control of micturition and can be highly effective in well-motivated individuals, although there is a recognised high relapse rate. Recent studies suggest that initial bladder retraining in the hospital may be more successful than outpatient bladder drill. However, drug therapy is the mainstay of treatment for OAB, and from the number of preparations that have been studied, it is clear that there is no ideal drug for all the people. In the past, clinical results of treatment have often been disappointing due both to poor efficacy and unacceptable adverse effects. Earlier preparations were not subjected to the current rigorous randomised controlled trials and, therefore, lack evidence-based data. Comparison of drug therapies for this condition is difficult due to the placebo effect of 30– 40%, and since the response to any of the available drugs is only in the region of 60%, any differences that are detected are likely to be small, and thus require large-scale studies to show efficacy. Historically, this has led to a paucity of comparative data, though this has begun to be addressed in recent years in large-scale studies such as STAR, in which tolterodine XL (4 mg) and solifenacin (5 and 10 mg) were compared. The drugs that are currently prescribed for OAB have an antimuscarinic component, which means that there is no alternative ‘class’ of drug to prescribe, and this limits compliance with treatment because of a lack of acceptability to some people. However, recent advances have included sustained release preparations of existing compounds, innovative routes of administration and newer antimuscarinic preparations. Such innovations are welcome and may represent more suitable choices for many people. While many people will be considerably improved and even cured of their symptoms by drug therapy, there are always those who do not respond and for them, it is most important that further investigations are undertaken to ensure that the correct problem is being addressed. Urodynamic studies will confirm (or otherwise) a diagnosis of detrusor overactivity in which case, further trials of different antimuscarinic preparations would be desirable, whereas in the absence of proven detrusor overactivity, an alternative diagnosis should be sought to avoid further ineffectual treatment and, hence, disillusionment and waste of resources. This supplement has been written by experts in the OAB and its management, and it addresses the challenges facing healthcare professionals who care for the many sufferers of this common and troublesome problem.