Definition of overactive bladder and epidemiology of urinary incontinence.

OBJECTIVES: To review the definition of the overactive bladder and to summarize the results of epidemiologic studies on this specific disorder as well as urinary incontinence (UI) in general.
METHODS: From a literature search covering the time period from 1954 through 1995, 48 epidemiologic studies and several other publications dealing with the prevalence and natural history of UI were reviewed. A meta-analysis of reported data was performed with respect to incontinence definitions, investigation methods, home country of survey, sex, and age groups.
RESULTS: Differences in definitions of incontinence, target populations, and study design in different investigations resulted in inhomogeneity and difficulties of comparing the available data. By grouping the studies with respect to similarities in the above-mentioned criteria and analyzing the results for each group of studies, an attempt was made to understand the great variation of reported results. Differences in prevalence of incontinence were identified for all examined groups of studies and for distinct ethnic populations. Scarce information about incidence, spontaneous remission rates, and risk factors was used to elucidate the natural history of UI in women and men.
CONCLUSIONS: Although generally accepted definitions of the overactive bladder specifically and UI in general are highly desirable, they have not yet been established. Such definitions should comprise aspects of severity and demonstrability of the condition, bother factor, and impact on quality of life. Moreover, basic requirements for epidemiologic surveys of incontinence, such as validation of questionnaire results, need to be defined and standardized to create a sensible basis for useful epidemiologic studies in the future.