Overactive bladder (OAB) is a symptom complex consisting of urge urinary incontinence, urgency, and frequency. Although the prevalence of this condition has not yet been well defined, a recent study suggests that OAB affects approximately 16.0% of men and 16.9% of women in the United States.¹ The total US economic cost of OAB was approximately $12.02 billion in 2000.² As the population continues to age, the prevalence of OAB, as well as its associated costs, is expected to rise.

OAB can be debilitating to those suffering with the disorder, affecting their quality of life, sleep patterns, and mental health.¹ However, only a small proportion of persons with this condition receive medical treatment for their symptoms. In addition, the pharmacologic agents used to treat OAB are often limited by issues of efficacy and tolerability. Although clinical trial data support the efficacy of antimuscarinic therapy for OAB, many patients discontinue treatment because of unacceptable side effects, most notably, dry mouth. The availability of extendedrelease formulations has improved the treatment of OAB by offering once-a-day dosing with a reduced side-effect profile. In addition, transdermal OAB therapy is now available that appears to provide efficacy similar to that of the extendedrelease formulations with an even lower incidence of adverse events.

In August 2003, a roundtable meeting was held in Montreal to discuss the current and future treatment strategies for OAB. This supplement is based on the presentations and discussions that took place at that event.

Paramount to providing OAB patients with improved treatment options is an understanding of the pathophysiology underlying the condition. Although the exact mechanisms responsible for the development of OAB have yet to be fully elucidated, much progress has been made. Naoki Yoshimura, MD, PhD, and Michael B. Chancellor, MD, begin this supplement with an overview of the current state of knowledge regarding the neurophysiology of lower urinary tract function and dysfunction. In addition, they discuss how our widening understanding of neurourology can be translated into novel drug targets for the treatment of OAB.

Roger R. Dmochowski, MD, follows with an overview of the treatment options currently available for patients with OAB. In addition, Dr Dmochowski discusses the therapeutic implication of data from recent OAB clinical trials, emphasizing the benefit of combined pharmacologic and behavioral therapy to maximize patient outcomes. Scott MacDiarmid, MD, then discusses the surgical and pharmacologic management of mixed incontinence. He presents the data supporting the use of antimuscarinic agents for the treatment of this condition and describes factors that may influence patient response to both surgical and pharmacologic therapies.

David R. Staskin, MD, focuses on the principles behind transdermal therapy for OAB. He provides an overview of the different transdermal systems available and explains the advantages of this method of drug delivery. Victor W. Nitti, MD, then discusses the practical issues behind the use of transdermal OAB therapy. He describes the transdermal system currently available, namely, oxybutyinin TDS, and discusses possible improvements for this delivery system.

Rodney A. Appell, MD, concludes the supplement with a review of specific OAB patient populations, including pediatric, geriatric, and pregnant patients; men with prostatitic obstructions; and patients in whom OAB is of neurogenic origin. He discusses the unique issues regarding the use of antimuscarinic agents in these defined populations.

I hope that you find this supplement informative and useful. With the development of new therapies, as well as methods with which to deliver them, we can continue to improve OAB treatment for this underserved patient population.