Published Online: February 18, 2014
J. Quentin Clemens, MD; Chieh-I Chen, MPH; Tamara Bavendam, MD; Kelly H. Zou, PhD; Amir Goren, PhD; and Shaloo Gupta, MS
Objectives: To assess the impact of overactive bladder (OAB) symptoms on work productivity and daily activities, and estimate the annual costs of OAB-related work productivity impairment in currently treated versus never-treated subjects.
Study Design: A self-administered, Internet-based survey of US adults with OAB symptoms.
Methods: Of 24,866 screened adults in the 2009 National Health and Wellness Survey (NHWS), 2887 qualified for a followup OAB survey, with 2750 completing all survey questionnaires. Multivariate analyses were used to identify signifi cant predictors of OAB-related work productivity and daily activity impairment.
Results: Of 2750 respondents, 1171 were classified as OAB-treated (receiving prescription therapy; n = 549) or OAB-untreated (never treated; n = 622). Lack of OAB prescription treatment, younger age, male sex, unemployment, nonsingle marital status, and increased OAB symptom count and bother were signifi cant (P <.03) predictors of impaired daily activity in multivariate analyses. Among 476 respondents who were employed (193 OAB-treated; 283 OAB-untreated), absenteeism was significantly associated with younger age, male sex, and black ethnicity (P <.04); overall work productivity impairment was associated with lack of OAB treatment, younger age, male sex, and increased OAB symptom count and bother (P <.01). Estimated annual costs (2009 US dollars) associated with OAB-related work impairment were $9670 for OAB-treated subjects versus $17,477 for OAB-untreated subjects.
Conclusions: OAB can cause impairments in daily activity and work productivity, especially among younger untreated subjects. Annual costs of OAB-related work productivity impairment are nearly twice as high for never-treated versus currently treated subjects. Am J
Pharm Benefits. 2014;6(1):19-26
Overactive bladder (OAB) has been defined by the International Continence Society as urinary urgency, with or without urgency urinary incontinence, usually associated with increased daytime frequency and nocturia, in the absence of urinary tract infection or other obvious pathology.1,2 In turn, urgency has been defined as a sudden, compelling desire to pass urine without delay.1 The overall prevalence of OAB in adults 18 years or older has been estimated at 16% to 17% among men and women in the United States, with prevalence increasing with advancing age.3 The effect of age can be seen in the higher prevalence reported among 20,000 US adults 40 years or older who participated in the Epidemiology of Lower Urinary Tract Symptoms (Epi- LUTS) study, in which OAB symptoms were reported at least “sometimes” by 27.2% of men and 43.1% of women.4 By 2018, it is projected that 546 million adults 20 years or older throughout the world will be affected by OAB.5
Current treatment rates for OAB are low,6 which is a concern because OAB symptoms can have a negative impact on health-related quality of life, including physical, psychological, vocational, and social functioning, and the performance of routine daily activities.3,7,8 The functional impairment associated with OAB contributes to its economic burden.9,10 Although effective treatments (ie, antimuscarinic agents, behavioral therapies) are available to manage OAB symptoms, 11,12 many individuals do not discuss their symptoms with a healthcare provider and therefore are not prescribed treatment for OAB.6,13
The present study evaluated OAB-related impairment in work productivity and daily activity among treated and never-treated US subjects with OAB symptoms using data from a National Health and Wellness Survey (NHWS) subpopulation. From these analyses, annual indirect costs associated with OAB-related work productivity impairment were estimated and factors that predicted impairment in work productivity and daily activity were identified.
Study Design and Subjects
The NHWS was a self-administered, Internet-based questionnaire given in 2009 to a nationwide sample of 75,000 adults in the United States. The NHWS respondents were recruited via stratifi ed random sampling on the basis of demographics reported by the US Census Bureau to represent the total US adult population. A total of 24,866 respondents from the 2009 NHWS data set were screened for OAB symptoms with the OAB Awareness Tool14 and prespecifi ed inclusion and exclusion criteria (listed below); 2887 respondents reported a history of OAB symptoms and qualifi ed for a follow-up OAB survey; 2750 qualifi ed respondents completed the follow-up OAB survey.
For inclusion in the survey, subjects had to be 18 years or older, able to read and write English, and willing to provide personal health information. The presence of OAB symptoms was documented by current use of medication to control OAB symptoms and by scores higher than 14 (for men) or higher than 16 (for women) on the 8-item OAB Awareness Tool (score range, 0 to 40),14 with screening scores of 8 or higher indicating possible OAB. Exclusion criteria included current pregnancy, selfreported hematuria or pink-tinged urine, pain or burning sensation on urination due to urinary tract infection, use of a catheter, diagnosis of benign prostatic hyperplasia (BPH) or prostate cancer, or current use of medication for BPH (eg, tamsulosin, dutasteride).
The 2750 qualified respondents who completed the follow-up OAB survey were classifi ed into 3 groups: 549 (20%) who were currently taking a prescription OAB medication (OAB-treated); 622 (23%) who had never taken a prescription OAB medication, although they may have been receiving nonpharmacologic treatment, such as behavioral modification (OAB never-treated); and 1579 (57%) who had ceased taking prescription OAB medication (OAB past treatment). The never-treated subjects reported that they believed that their bladder control condition would probably get worse over time and require treatment with medications. Subjects who were not currently being treated but had been treated at some time in the past were excluded from further analyses to avoid any confounding effects associated with differences in the reasons for discontinuing previous treatment. Of 1171 OAB-treated and never-treated subjects, 476 (41%) reported that they were employed (full-time, part-time, or self-employment).
OAB Survey Assessments
The Work Productivity and Activity Impairment (WPAI) questionnaire was used to assess impaired work productivity and daily activity function due to OAB symptoms over the past 7 days.15 Employed subjects indicated the number of hours they missed from work due to OAB symptoms, the number of hours they missed for any other reason, and the total number of hours they worked. The degree of impairment in work productivity or daily activities is rated on a scale on which 0 equals no impairment and 10 equals total impairment. From these data, 4 subscales (ie, absenteeism, presenteeism, percentage of overall work impairment, and percentage of overall activity impairment) were generated. Absenteeism refers to the percentage of hours missed at work in the previous week. Presenteeism refers to the percentage of impairment in productivity during the hours worked. Overall work impairment is the total impact of absenteeism and presenteeism. Activity impairment is the percentage of impairment during nonwork daily activities. Only subjects who were currently employed were included in the assessments of absenteeism, presenteeism, and overall work impairment, whereas all subjects were included in assessments of daily activity.
Subjects provided socioeconomic and demographic information and completed items following up on symptoms identifi ed in the OAB Awareness Tool. Overactive bladder symptoms experienced in the past month, regardless of whether they were rated as bothersome on the OAB Awareness Tool, were summed (symptom count).14 Subjects also rated the degree to which bothersome symptoms changed in severity over the past year (scores from 1 for a substantial decrease to 7 for a substantial increase), and symptom scores were averaged to calculate the overall change (symptom bother).16 Generic health-related quality of life was assessed with the 12-item Short-Form Health Survey (SF-12, version 2) with Physical Component Summary and Mental Component Summary scores, each ranging from 0 (poorest state of health) to 100 (highest state of health), normalized to the US population (mean [standard deviation] score = 50 ).17 Responses to the SF-12 v2 were used to generate the Short-Form Six-Dimension Health Utility score, a preference-based single index of health status (physical functioning, role participation, social functioning, pain, mental health, and vitality) using general population values; scores range from 0 to 1, with 1 representing optimal health.18
Finally, the Charlson Comorbidity Index assessed the 10-year risk of mortality associated with the presence of any of 19 conditions, each of which is assigned a numeric score (1, 2, 3, or 6; higher scores indicate more lethal conditions), with the index score equaling the sum of the scores.19
As the NHWS is stratified by sex, age, and race/ethnicity, all bivariate results (comparing OAB-treated and never-treated populations) were weighted to reflect adult population values from the US Census. Demographic and socioeconomic characteristics, quality of life, and assessments of work productivity and daily activity impairment due to OAB symptoms were compared between OAB-treated and never-treated subjects using either a 2-sample t test for continuous data or a χ2 test for categorical data (significance level, 2-sided P <.05).
Indirect costs associated with work productivity impairment were calculated using the US Department of Labor’s 2009 Bureau of Labor Statistics average wages (2009 US dollars), with adjustments for sex and age. The adjusted wages were multiplied by the percentage of impairment in work productivity and then annualized to provide an estimate of the projected annual per capita costs associated with lost productivity due to OAB.20 Annual costs related to work productivity impairment due to OAB symptoms were compared between OAB-treated and never-treated subjects, using 2-sample t tests.
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