We conducted a cross-sectional study in Italy among men at least 50 years old and women at least 40 years old who consecutively visited their general practitioners. Patients were asked about the frequency of symptoms of overactive bladder and urinary incontinence. A total of 9613 men (mean age, 64.8 years; range, 50–98 years) and 13,365 women (mean age, 60.3 years; range, 40–98 years) were identified by 774 general practitioners. The frequencies of overactive bladder were 3.0% (95% confidence interval, 2.7–3.5) in men and 1.1% (95% confidence interval, 0.9–1.3) in women. The corresponding frequencies for urinary incontinence were 8.3% (95% confidence interval, 7.7–8.9) in men and 10.2% (95% confidence interval, 9.6–10.8) in women.
The reported prevalence of urinary incontinence ranges from 10% to 50%.11-9 The differences can be explained in part by the age distribution of the populations considered, with higher rates in studies including more older subjects.2,10 Further, some studies were conducted in selected populations.7,11
With regard to diagnosis, although urinary incontinence should be an objectively proven condition of involuntary loss of urine, the criteria for its definition vary.12 Differences also have been reported in the frequency of various types of urinary incontinence (urge, stress, and mixed incontinences),11,13-16 and data are scant on the frequency of overactive bladder without urinary incontinence.16 We therefore conducted a study in Italian men at least 50 years old and women at least 40 years old to determine the prevalence of overactive bladder and various types of urinary incontinence.14
Materials And Methods
Eligible subjects were consecutive men at least 50 years old and women at least 40 years old who asked to be seen by their general practitioners during the study period. There were no exclusion criteria. Age cutoffs were chosen because of the very low rate of urinary incontinence in men younger than 50 years and in women younger than 40 years.2
Participating general practitioners were invited to take part in the study on the basis of lists of general practitioners specifically interested in epidemiologic studies and affiliated with the Gruppo Interdisciplinare di Studio Incontinenza Urinaria (Interdisciplinary Group for the Study of Incontinence). Each general practitioner could decide when to start recruitment (generally soon after agreeing to participate) and stopped when 50 cases had been identified, or after 5 days. The motivation for participating was purely an interest in the data collection. All participating physicians were general practitioners, without any specific interest in urogynecological problems.
We obtained demographic information from each subject. The subjects were then asked: Have you had any involuntary urinary loss during the past 3 months? On average, do you urinate more than 8 times a day and/or more than once during the night? Have you any urgency symptoms? If the subject answered yes to the first question, that subject was defined as having urinary incontinence; if the subject answered yes to the second and third questions, that subject was considered to have overactive bladder.
Subjects with incontinence were interviewed further with the questionnaire proposed by Wein and colleagues17,18 for diagnosis of type of urinary incontinence: stress incontinence, mixed incontinence, or urge incontinence. The questionnaire provides a presumptive diagnosis of stress and urge incontinence on the basis of the presence or absence of the following symptoms: urgency, frequency with urgency, leaking during physical activity, amount of urinary leakage with each episode of incontinence, ability to reach the toilet in time after an urge to void, and nocturia. The criteria for overactive bladder without urinary incontinence (ie, patients reporting an urge to urinate more than 8 times a day and/or more than once during the night and/or with urgency symptoms) and various types of urinary incontinence were the criteria accepted by the main Italian research groups on urinary incontinence.
Informed consent was obtained from each subject. Participation in the study did not commit the patient to any instrumental examination or laboratory tests. Confidence intervals (CI) of the estimated percentages of frequency of urinary incontinence were based on the Poisson approximation. Statistical differences in the frequency of urinary incontinence among strata of age and sex were analyzed with the standard chi square test comparing observed and expected events and, when appropriate, using the test for trend.
Results
A total of 9858 men and 13,671 women were identified by 774 general practitioners, representing approximately 1.5% of all Italian general practitioners. Of those, 26.6% were in northern Italy, 17.4% were in central Italy, and 56.0% were in southern Italy. Each general practitioner identified a mean of 30 subjects (range, 15–50). A total of 245 men (2.5%) and 306 women (2.2%) refused to enter the study. Thus the present report included information on 9613 men (mean age, 64.8 years; range, 50–98 years) and 13,365 women (mean age, 60.3 years; range, 40–98 years).