DEFINITION, EPIDEMIOLOGY, AND IMPACT
Urgency urinary incontinence is a subset of overactive bladder characterized by urinary urgency with incontinence.
Mixed urinary incontinence includes women with both urgency and stress urinary incontinence.
The International Continence Society (ICS) has defined bladder storage abnormalities that include urinary incontinence, its subtypes, and overactive bladder (OAB) syndrome.1 Although urinary incontinence is simply “involuntary loss of urine,” its three major subcategories are stress urinary incontinence (SUI), urgency urinary incontinence (UUI), and mixed urinary incontinence (MUI). SUI is the “involuntary loss of urine on effort or physical exertion or on sneezing or coughing.”1 UUI, the focus of this chapter, is incontinence associated “with the sensation of a sudden, compelling desire to void that is difficult to defer.”1 UUI is a subset of OAB syndrome, defined by the ICS as urinary urgency, usually accompanied by frequency and nocturia, with or without UUI in the absence of urinary tract infection or other obvious pathology.1 Lastly, MUI is a combination of SUI and UUI and is defined as “involuntary loss of urine associated with urgency and also with effort or physical exertion or on sneezing or coughing.”1 The interrelationships between OAB, SUI, UUI, and MUI are illustrated in Figure 6-1.
Interrelationship of overactive bladder, urgency urinary incontinence, mixed urinary incontinence, and stress urinary incontinence.
Attempts to ascertain OAB and UUI prevalence and incidence have been hampered by lack of standardization of definitions including the frequency or severity of symptoms in epidemiologic studies. Nonetheless, based on a recent summary, estimates of OAB and UUI prevalence in Europe, Asia, and the United States are relatively consistent.2 The prevalence of OAB in the United States is approximately 15% and UUI is as high as 11%.2 Occurrence of both UUI and OAB is associated with increasing age (Figure 6-2). UUI incidence in the United States is four to five women per thousand in the 35- to 55-year age group,3 and increases to 7 to 17 women per thousand4,5 in women older than 60 years. The few studies that address remission of UUI report annualized remission rates ranging from 11% to 22.7% in older women.4,5 These reports and other recent work indicate that UUI is a dynamic state over the short term.4-6 Although no studies have evaluated the lifetime natural history of OAB and UUI, data from the Agency for Healthcare Research and Quality (AHRQ) suggest that over the long term women ultimately develop persistent symptoms.2
Prevalence of type of incontinence (% on y axis) compared to age (in years on x axis). (Reprinted with permission from Ref.10)
Approximately one-third ...