Epidemiology and psychosocial impact of female pelvic floor disorders

Prevalence.

Prevalence rates reflect the total number of cases of disease in the population at a given time. For urinary incontinence, definitions used in the literature range from using the presence of leakage (yes/no) to using the frequency of leakage (daily, weekly, monthly, ever) to using symptom bother to determine prevalence. Different definitions can lead to variability in reported prevalence and incidence rates ( ).

A review of 21 studies by found the average prevalence of any incontinence for older women was 34%, and 12% for daily incontinence. For middle-aged and younger adults, the average prevalence of any incontinence was slightly lower, at 25%, in the same study. analyzed the National Health and Nutrition Examination Survey (NHANES) and used a more strict definition, defining incontinence as “at least weekly leakage or monthly leakage more than drops.” Based on this definition, the authors reported a prevalence of 15.7%. Also using NHANES data, reported a prevalence of 51% when incontinence was defined as any positive response. Table 6.1 summarizes the prevalence of urinary incontinence based on age group and varying definitions.

Prevalence rates also vary based on symptom severity. Again using NHANES data, reported that the prevalence of any urinary incontinence in women aged 50 to 59 years was 19.9% for “mild” incontinence, 16.5% for “moderate” incontinence, and 25% for “severe” incontinence. These prevalence rates remained stable from 2005 to 2010 ( ). Variable prevalence rates were also seen in other age groups based on symptom severity.

The type of urinary incontinence is also important when considering the prevalence of the condition, in addition to age ( Fig. 6.1 ). The prevalence of stress urinary incontinence ranges from 33% to 54%, of urgency urinary incontinence ranges from 12% to 16%, and of mixed urinary incontinence ranges from 19% to 50% in populations reporting any incontinence. Similar data are available from multiple countries documenting that these conditions are highly prevalent worldwide.

Incidence, remission, improvement, and progression.

Urinary incontinence is a dynamic condition, and symptoms may wax and wane. Incidence rates reflect the number of new cases of disease in the population during a specified period of time. The average one-year incidence ranges from 6.9% to 11.1% in the United States in women younger than 55 years ( ; ). The rate is higher in older women, estimated to be 13.8% over 1 year in women 54 to 79 years of age. Reported 1-year remission rates range from 4.6% to 9.1% ( ; ; ). In one meta-analysis by , age-specific incidence was less than 2/1000 person-years in women younger than 40 years, 5/1000 person-years at age 50 years, and 3/1000 person-years at 60 to 65 years, but then increased in later decades in life. In a study by that analyzed data from the Nurse’s Health Study, the authors reported that most women reported persistence or progression of urinary incontinence symptoms over time, with few (3%–11%) reporting remission. Younger women and those with less severe symptoms were more likely to report remission or improvement over 10 years. In a follow-up study, evaluated the natural history of urinary incontinence by subtype and found that most women with incident stress and urgency urinary incontinence continued to experience similar subtype symptoms over an 8-year time period. Women with more severe incident symptoms and obese women were more likely to have persistent symptoms or progress to mixed urinary incontinence over time. Only 4% to 12% reported resolution of their urinary incontinence over the time period.

Urinary incontinence during pregnancy and postpartum.

Stress urinary incontinence is common during pregnancy, with a prevalence ranging from 40% to 59%. In general, the severity may worsen throughout pregnancy. In postpartum women, stress urinary incontinence will resolve in many, and the prevalence is estimated to range from 15% to 30% ( ). In longitudinal studies, the cumulative incidence rate of urinary incontinence is estimated to be approximately 39% ( ). Up to 26% of women who report urinary incontinence during pregnancy will have persistent leakage in the postpartum period; the majority will have resolution. In a large cohort study by , women were followed annually for up to 5 years after their first delivery. During follow-up, the incidence of bothersome stress urinary incontinence was 2.5/100 woman-years, and for overactive bladder it was 1.7/100 woman-years. Urinary incontinence was more common in the vaginal birth group compared to those who received cesarean section, but the differences lessened as time from childbirth increased. reported that, following spontaneous vaginal delivery, the 15-year cumulative incidence of stress incontinence was 34.3%, and of overactive bladder was 21.8%. Compared with spontaneous delivery, cesarean delivery was associated with a significantly lower risk of developing either condition during the time period.

Costs.

The financial burden of urinary incontinence and overactive bladder syndrome is significant and includes direct and indirect costs. Direct costs include costs to the patient for routine care (absorbent products, laundry), medical visits, and treatments. Indirect costs include loss of productivity and costs of paid or unpaid caregivers, which are more difficult to measure ( Table 6.2 ). Many studies support that the largest cost item associated with urinary incontinence for both community-dwelling women, as well as those in nursing homes, remains routine care and supplies, with only a minimal proportion of the costs going to evaluation and treatment. Although most studies evaluate the direct costs because of accessibility of data, the economic impact of indirect costs should not be underemphasized.

A study by estimated that the annual direct cost of urinary incontinence for women was $12.4 billion (2001 US dollars), and the largest cost category was routine care (70% of costs), followed by nursing home admissions (14%), treatment (9%), complications (6%), and diagnosis and evaluation (1%). Medicare spending on incontinence treatment continues to increase dramatically. For Medicare beneficiaries aged 65 years and older, used multiple national databases and reported that the expenditures for inpatient and outpatient medical care doubled from $128 million in 1992 to $234 million in 1998. They also estimated that 23% of incontinent women missed an average of 28.7 hours of work because of inpatient and outpatient care associated with urinary incontinence treatment. A systematic review by that focused on urgency urinary incontinence reported that the projected total cost including direct, indirect, and intangible costs would be $76.2 billion in 2015 and $82.6 billion in 2020 in the United States alone.

At the individual level, annual routine costs alone in 2005 were estimated to be $250 to $900 per woman ( ). Direct costs for incontinence management increase significantly with greater incontinence frequency. evaluated the impact of incontinence improvement on incontinence-associated costs and found that the mean cost for an individual decreased by 23% for each decrease of seven incontinence episodes per week. Because most of the cost associated with incontinence care is out of pocket, patients assume great financial responsibility in managing this condition.

Prevalence, incidence, remission, and progression.

Most population-based surveys define prolapse based solely on patient symptoms, commonly defined as an affirmative response to seeing/feeling a vaginal bulge. Using this definition, the prevalence of prolapse symptoms ranges from 2.9% to 8% in the United States ( ; ; ). These studies did not include physical examination information. Additional studies from the Women’s Health Initiative (WHI) including US women aged 50 to 79 years found the prevalence of any degree of prolapse based on examination alone of grades 1 to 3 prolapse to be 41.1% ( ; ). Table 6.3 presents the estimated prevalence of prolapse. Prevalence estimates based on examination findings alone are higher compared with those based on symptom reports alone.

Data are limited for the incidence and remission of pelvic organ prolapse. Based on the WHI data, the incidence of grades 1 to 3 prolapse is estimated to be 9.3/100 woman-years for cystocele, 5.7/100 woman-years for rectocele, and 1.5/100 woman-years for uterine prolapse. The remission rates are estimated to be up to 9%, with cystocele having higher remission rates than rectocele. Prolapse progression ranged from 1.9% for uterine prolapse, to 9.5% for cystocele, and 14% for rectocele. Older, parous women are more likely to develop new or progressive prolapse than to regress. Progression and resolution appear to be dependent on baseline severity of prolapse.

After pregnancy and delivery, 31% of women have stage 2 prolapse. After delivery, 14% to 15% of women have prolapse at or below the hymen, and 5% have this after cesarean delivery. In a longitudinal study by , women were enrolled 5 to 10 years from their first delivery and followed annually for 4 to 9 years. The majority of women demonstrated worsening in pelvic support over time, and vaginal birth was associated with worse support 5 years from delivery and more rapid deterioration in apical support.