Karin Coyne, MEDTAP International, 7101 Wisconsin Avenue, Suite 600, Bethesda, MD 20814, USA. E-mail: email@example.com
Objectives: Overactive bladder (OAB) is described as urinary urgency, with and without urge incontinence and usually with frequency and nocturia. Most attention to OAB's impact on health-related quality of life (HRQL), however, has focused on urge incontinence. The objective of this study was to evaluate the burden of OAB, specifically urinary urgency and frequency on HRQL.
Methods: In the National Overactive Bladder Evaluation Program (NOBLE), a computer-assisted telephone interview survey was conducted to assess the prevalence of OAB in the United States. Based on interview responses, respondents were classified into three groups: continent OAB, incontinent OAB, and controls. To evaluate the HRQL impact of OAB, HRQL questionnaires were mailed to all respondents with OAB and age- and sex-matched controls as a performed nested case–control study. Continuous data were compared using Student's t tests and analysis of variance with post hoc pairwise comparisons; results were adjusted for age, sex, and comorbid conditions. Multivariable regressions were performed to assess the impact of each urinary variable on symptom bother and HRQL.
Results: A total of 919 participants responded to the questionnaires (52% response rate) with a mean age of 54.2 years (SD 16.4 years); 70.4% were female and 85% were white. Continent OAB participants comprised 24.8% of the sample, incontinent OAB 18.3%, and controls 56.9%. In each regression analysis, urinary urge intensity accounted for the greatest variance for increases in symptom bother and decreases in HRQL.
Conclusions: The experience of urinary urgency has a significant negative effect on HRQL and increases symptom bother, an effect that, in this community sample, is greater than that of incontinence, frequency, or nocturia.
Urinary urgency (a sudden, compelling desire to urinate, which is often difficult to defer), with or without urge incontinence, and usually with urinary frequency and nocturia, can be described as “overactive bladder” (OAB) . Previous studies have investigated the impact of OAB on health-related quality of life (HRQL) to find that urinary incontinence has a negative impact on physical, social, and psychological well-being and interferes with daily activities [2–6]. Although the impact of urinary urge incontinence on HRQL has been widely studied, the effects of continent OAB symptoms, namely, urgency and frequency, have not. The prevalence of continent and incontinent OAB is estimated to be 16.6% or approximately 33 million men and women in the United States  and 6% to 35% in Europe . The prevalence of continent OAB in the United States is estimated to be 7.6% in women and 2.6% in men . Given this, the impact of continent OAB symptoms on HRQL warrants further examination.
Although urge incontinence has received more attention as a symptom of OAB, it is not the most frequent symptom of OAB. Milsom et al.  found urinary frequency and urgency to be reported more frequently than urge incontinence. Robinson et al.  found “number of voids/day” and “times awakened at night” to be predictive of HRQL indicating that other symptoms of OAB, not just incontinence, affect HRQL. In a sample of women seeking care for troublesome symptoms at an urodynamic clinic, Norton et al.  found that 34% of the women were continent with symptoms of urgency, frequency, and nocturia. Liberman et al.  evaluated the impact of both continent and incontinent OAB symptoms on HRQL in a population-based survey and found that participants with symptoms of continent OAB reported significant decrements in the mental health, health perception, and bodily pain subscales of the Medical Outcomes Study (SF-20) when compared to normal controls from the survey. Thus, although the impact of incontinent OAB on HRQL appears to be greater than continent OAB, continent OAB also appears to have adverse effects on HRQL. The purpose of this study was to investigate the impact of all OAB symptoms on HRQL in a national community sample in the United States.
Using a clinically validated computer-assisted telephone interview (CATI), a national telephone survey was performed to estimate the prevalence of OAB in the United States . Quota sampling methods were used to ensure a representative US population with respect to age, sex, and geographic region. A total of 5204 people were surveyed and the prevalence of OAB was 16% in men and 16.9% in women . As a follow-up to the national telephone survey, a nested case–control study was conducted among people meeting OAB case criteria and age- and sex-matched controls who were invited to complete a battery of self-administered questionnaires related to HRQL, sleep, and depression. Institutional review board approval was obtained before study initiation and all participants provided informed verbal consent before data collection was initiated.
The CATI survey included questions about demographics, work status, childbearing history, exercise, social activities, sleep habits, and fluid intake. Questions regarding the urinary symptoms of frequency, urgency, nocturia, and urge or stress incontinence as well as coping behaviors during the 4-week recall period preceding the telephone interview were asked. To aid in differentiating diagnosis, questions regarding urinary symptoms associated with urinary tract infections and prostate problems as well as questions regarding other physician-diagnosed comorbid conditions (e.g., congestive heart failure, diabetes) were also asked. During the interview process, participants were asked three questions regarding urgency: 1) “Did you have a sudden and uncomfortable feeling that you had to urinate soon?”; 2) “Did you have such a strong urge to urinate that you had to stop what you were doing and rush to the bathroom because you might lose urine?”; and 3) “People sometimes feel a sudden urge to urinate. Has this happened to you in the past 4 weeks?” Participants who responded “yes” to any one of the three questions were asked to rate their urge intensity on a scale of 1 to 10 with 1 being “feel some urge, but do not have to go right away” and 10 being “have to stop what you are doing and urinate immediately.” Participants who responded “no” to experiencing urgency were scored as a “0” on the urge intensity rating scale.
To avoid including participants with possible metabolic or pathologic conditions that could mimic OAB-like symptoms, cases were defined according to the telephone survey responses using the following criteria:
1Continent OAB cases included at least four episodes of urgency over the past 4 weeks plus more than eight voids per day (waking hours) or at least one bladder control coping behavior (e.g., decreased fluid intake, defensive voiding, travel restricted to places with known bathroom availability).
2Incontinent OAB included the continent OAB criteria, plus at least three episodes of urge incontinence over the past 4 weeks.
These criteria were designed to optimize the sensitivity and specificity of the clinicians’ diagnosis.
Nested Case–Control Study Questionnaires
Overactive bladder questionnaire (OAB-q). The OAB-q consists of an 8-item symptom bother scale and 25 HRQL items, which comprise four subscales (coping, concern, sleep, and social interaction) and a total HRQL score. The OAB-q is a clinically validated OAB-specific HRQL instrument with demonstrated high internal consistency and construct and discriminant validity . The symptom bother and HRQL subscale scores and total HRQL score are transformed to a 0 to 100 scale with higher scores on the HRQL subscales indicating better HRQL. Higher symptom bother scores indicate greater symptom bother.
Medical outcomes study short-form 36 (SF-36). The SF-36 is a self-administered generic health status questionnaire that is composed of eight domains: physical function, role limitations-physical, vitality, general health perception, bodily pain, social function, role limitations-emotional, and mental health. The SF-36 has been used extensively as an indicator of HRQL with well-documented reliability and validity . Lower scores indicate poorer function.
Center for epidemiologic studies depression scale (CES-D). The CES-D is a 20-item scale that was developed to assess depressive symptoms and has demonstrated reliability and validity [14,15]. The possible score range is from 0 (not at all depressed) to 60 (very depressed) with a cutoff score of 21 as an indicator of major depressive symptoms .
Medical outcomes study sleep scale (MOS-sleep). The MOS-sleep scale is a self-administered 12-item questionnaire that has been shown to be reliable and valid [17,18]. This scale assesses various characteristics of sleep including sleep disturbance, sleep quality and duration, and restfulness. A higher score on the MOS-sleep subscales is indicative of poorer quality of sleep . The Sleep Problems Index I subscale, which consists of six items related to sleep adequacy and disturbance, was used in this analysis.
All analyses were performed using SAS version 8.02 (SAS Institute, Inc., Cary, NC). Demographic variables and clinical conditions were evaluated by descriptive analyses. Chi-square tests were used to evaluate categorical data; t tests and analyses of variance (ANOVA) were used to evaluate continuous data. To compare the HRQL and symptom bother scores for normal controls, continent OAB, and incontinent OAB participants, ANOVAs with post hoc pairwise comparisons were performed; P values, however, were not adjusted for multiple comparisons because this examination of the data was considered exploratory. Adjustments for age, sex, and comorbid conditions (i.e., diabetes, congestive heart failure, prostate problems, previous bladder surgeries, history of cancer, number of births, and use of diuretics) were performed in the case–control comparisons. A series of multivariable regression models were performed to ascertain the effects of urinary urge intensity, frequency episodes, number of nocturia episodes, and number of incontinence episodes on symptom bother and each of the HRQL OAB-q subscales while controlling for age, sex, and comorbid conditions. In the regression models, all urinary variables and age were continuous; all others were coded dichotomously. Multicollinearity was assessed using the variance inflation factor (VIF) following the general rule that the VIF should not exceed 10 . In all analyses, an alpha of <0.05 was considered statistically significant.
Of the 1769 OAB cases and age- and sex-matched controls, 919 participants returned their questionnaires (52% response rate) (Table 1). Overall, responders were more likely to be older, female, and white with 57% of incontinent OAB participants, 60% of continent OAB participants, and 53% of controls responding. Each group was representative of participants in the CATI survey. Cases with incontinent OAB were significantly older and more likely to be female than continent OAB participants or controls. Comorbid conditions differed significantly by case/control status with incontinent OAB cases reporting significantly greater rates of diabetes, congestive heart failure, use of diuretics, history of bladder surgery, use of bladder medications, and prostate problems (Table 2).
Participant reports of bladder surgery and prostate problems; no details provided.
Based on participant self-report and includes the following medications: antibiotics, cranberry pills, detrol, ditropan, tamsulosin hydrochloride, herbs, nitrofurantoin monohydrate, oxybutynin, and “not sure.”
Abbreviations: CHF, congestive heart failure; CNS, central nervous system.
The symptom bother scores of the OAB-q were significantly higher and the HRQL subscales (concern, coping, sleep, and social interaction) were significantly lower for the continent and incontinent OAB participants than normal controls (P < 0.0001), even after adjusting for age, sex, and comorbid conditions (Table 3). Additionally, incontinent OAB participants, those with urge incontinence in addition to frequency and urgency, reported significantly lower scores in all OAB-q subscales and higher symptom bother scores than continent OAB participants (P < 0.0001 for all). Similar results were found among the SF-36 subscales. Significant differences were noted among continent and incontinent OAB participants and controls; all P < 0.001 except in the mental health subscale where the difference between continent and incontinent OAB participant scores was P < 0.05.
Table 3. OAB-q subscale scores by OAB status, controlled for age, sex, and comorbidities
When examining the impact of urgency on HRQL, significant differences (P < 0.0001) in all OAB-q subscales were present between participants who experienced urgency versus those who did not (Table 4). For participants experiencing urgency, 43.4% reported CES-D scores ≥ 21, compared to 22.3% of those who did not experience urgency (P < 0.0001). Similar significant differences were noted in the Sleep Problems Index and SF-36 subscale responses. Participants with urgency reported poorer sleep quality on the Sleep Problems Index (P < 0.0001) and decreased HRQL on all SF-36 subscales (P < 0.0001). When examining respondent ratings of urinary urge intensity with the ratings divided into tertiles, significant differences were present among all three group ratings of urge intensity on the OAB-q subscales (Fig. 1) (P < 0.01). The mean urge intensity rating was significantly different by case/control status with the mean equaling 1.5 for normal controls, 4.8 for continent OAB participants, and 7.0 for incontinent OAB participants (all pairwise comparisons, P < 0.0001). When comparing the urge intensity rating groups using the generic questionnaires, significant differences (P < 0.05) were apparent only between the lowest and highest urgency rating groups in the Sleep Problems Index and in all SF-36 subscales; no differences were present using the CES-D.
Table 4. OAB-q subscales by presence of sudden urge, controlled for age, sex, and comorbidities
Sudden urge (n = 369)
No sudden urge (n = 544)
Higher scores indicate greater symptom bother and greater sleep problems.
Urinary frequency of eight times or more per day also had a significant negative impact on HRQL with significantly (P < 0.0001) reduced scores on all OAB-q subscales and a significant increase in symptom bother compared to participants with urinary frequency less than eight times per day (Table 5). Urinary frequency appeared not to have as great an impact on the SF-36 as did urgency. Significant differences (P < 0.05) were noted in only three of the subscales (general health, social function, and mental health) when comparing respondents with frequency of eight or more times with those with eight or fewer times per day. Significant differences (P < 0.01) were present in the Sleep Problems Index. Additionally, for those urinating eight or more times per day, 36.5% had a CES-D score of ≥ 21 compared to 28.8% urinating less than eight times per day (P = 0.03).
Table 5. OAB-q subscale scores: comparison by times urinating per day (less than eight vs. eight or more), controlled for age, sex, and comorbidities
Less than eight (n = 645)
Eight or more (n = 239)
Higher scores indicate greater symptom bother and greater sleep problems.
The presence of nocturia was related to decreases in HRQL scores and increases in symptom bother scores. Significant HRQL differences (P < 0.01) were noted with increasing episodes of nocturia per night in all OAB-q subscales except social interaction. Additionally, for respondents who experienced at least one episode of nocturia per night as few as three nights per week, significant (P < 0.0001) differences were seen in all OAB-q subscales when compared to those who experienced no nocturia. Of those experiencing nocturia one or more episodes per night, 41.4% scored ≥ 21 on the CES-D versus 30.9% with nocturia one or no episodes per night (P < 0.01). Significant differences (P < 0.01) between respondents with more than one nocturia episode versus those with one or no nocturia episodes were present on all SF-36 subscales and the Sleep Problems Index.
In the six multivariable regression models with each of the OAB-q subscales and total score as outcomes, all of the urinary variables were significantly associated with each OAB-q subscale, except nocturia in the social interaction subscale. In each model, urinary urge intensity had the highest F value of all variables and greatest association with decreases in HRQL and increases in symptom bother. Tables 6 and 7 contain the parameter estimates, standardized estimates, standard errors, and F and P values from the OAB-q symptom bother and coping subscales, respectively. Similar results were noted in the remaining OAB-q subscales and HRQL total score. Among the subscales, r2 ranged from 0.21 (social interaction) to 0.52 (symptom bother). The VIF was < 2.5 for all variables in each model indicating the absence of multicollinearity.
Table 6. Multivariable regression: symptom bother subscale model
The F value represents the magnitude of association between each independent variable and the dependent variable; the higher the F value, the stronger the association.
Model R2 = 0.35.
Urinary urge intensity
Times urinating/day (frequency)
Times urinating/night (nocturia)
Number of births
Congestive heart failure
History of bladder surgery
History of cancer
The number of incontinence episodes was the second largest contributor to HRQL impact and symptom bother in all subscales except in the sleep subscale where nocturia had a greater impact than incontinence episodes. A history of bladder surgery was the only comorbid condition that was significantly associated with each OAB-q subscale. Prostate problems, diuretic use, and history of cancer were significantly associated with the sleep subscale whereas history of cancer was also associated with the concern subscale. Importantly, sex, age, number of births, diabetes, and congestive heart failure were not significantly associated with any OAB-q scales. The regression models were repeated in the incontinent group alone to further examine the impact of each urinary variable among only incontinent OAB respondents. Interestingly, urgency intensity rating was again the most significant urinary variable in all models; number of incontinent episodes was not significant in any of the models. Nocturia was also significant in the sleep subscale whereas urinary frequency was significant in the coping and concern subscales.
Although urinary urgency and incontinence have been associated with increases in falls and fractures among the elderly , depression , and sleep disturbances [23,24], the personal burden of individual urinary symptoms on HRQL and daily activities has not been previously quantified. This research shows that although urge incontinence has a significant negative impact on HRQL, the effects of urinary frequency, urgency, and nocturia are far from negligible. In this community sample, the intensity of urinary urgency appears to have a far greater impact on HRQL and symptom bother than other OAB symptoms.
While controlling for age, sex, and multiple comorbid conditions, the regression analyses demonstrate that each symptom of OAB has a significant negative impact on HRQL and symptom bother. Nevertheless, the analyses also clearly show that urinary urge intensity has the strongest association and explains the greatest variance in symptom bother and decrements in HRQL. The number of incontinence episodes was significantly associated with all OAB-q subscales; however, incontinence did not account for the greatest variance in any OAB-q subscale even when analyzed in the incontinence group alone. This finding perhaps reflects the greater importance of urinary urge intensity on HRQL and symptom bother or may be indicative of the inability to control urgency. Incontinent OAB respondents reported the highest ratings of urinary urge intensity. For incontinent OAB patients, urinary urgency likely precedes the incontinent episode and although inherently linked to incontinence, the inability to control urgency appears to be more distressing than the incontinence itself. The effects of incontinence may be lessened or controlled to a certain extent with various preventive measures such as the use of pads, preventive voiding, and limiting fluid intake; however, the intensity of urinary urgency appears to be a symptom for which a patient has little to no control.
This research does not negate the previous well-documented findings as to the detrimental impact of incontinence on HRQL [2–6]. In this study, incontinent OAB respondents reported lower HRQL than continent OAB respondents. These findings do indicate, however, that the HRQL impact and symptom bother from OAB occur well before incontinence occurs; continent OAB symptoms are also bothersome and detrimental.
These findings provide evidence of an increased understanding as to the impact of the multiple symptoms of OAB. When analyzed either univariately or multivariately, the OAB-q symptom bother and HRQL subscales discriminated among people reporting the presence or absence of multiple OAB symptoms including urinary urgency, urinary frequency, nocturia, and incontinence. Surprisingly, age and sex were not significantly associated with any OAB-q subscales and the only consistent significant comorbid condition was a history of bladder surgery. Thus, despite significant differences in comorbid conditions and sex among the controls and continent and incontinent patient groups, the symptoms of OAB accounted for the most variance in each regression model.
The OAB-q was the most sensitive instrument in this study in detecting differences related to participant reports of OAB symptoms. Each symptom was also significantly related to other patient outcome measures (i.e., the SF-36, the MOS-sleep scale, and the CES-D), however, to a lesser extent than the OAB-q. This consistency in outcomes with multiple measures provides further evidence regarding the broad impact of OAB. These data also provide further support for the reliability and validity of the OAB-q as a measure of symptom bother and HRQL in respondents with either continent or incontinent OAB. Internal consistency reliabilities in this study ranged from 0.90 to 0.96 for the OAB-q subscales. These reliabilities are comparable to those reported in the OAB-q development and psychometric evaluation study . Based on recent recommendations [25–27], psychometric evidence is ideally needed from several independent studies using comparable populations of people with the target disorder to support the validity and reliability of HRQL instruments used to support regulatory labeling and/or promotional claims. Given the original development study and these new data, the OAB-q has acceptable evidence supporting its reliability and validity for evaluating the impact of OAB treatments on HRQL and symptom bother.
This research is limited in its design as a cross-sectional survey and subject to recall bias. Many important variables in this analysis (e.g., comorbid conditions, bladder medications) are based entirely on participant reports without clinical verification. Nevertheless, the generalizability of the results, given the size of the community sample and diverse geographic locations, is increased. This descriptive analysis provides new insight on the impact of multiple urinary symptoms on HRQL.
Urinary urgency is a quantifiable and bothersome symptom with significant HRQL impact and, as such, is a patient outcome that should not be overlooked. Given the findings of this study, urinary urgency and its impact merit further clinical inquiry to ascertain whether treatments may be warranted or desired. Additionally, given the importance of urinary urgency on HRQL in this community sample, the impact of this symptom should be further evaluated in a clinical setting.
The authors thank Innovative Medical Research for their data collections endeavors.
This research was funded by Pharmacia Corporation.