Stress urinary incontinence, the involuntary loss of urine with physical exertion, sneezing, or coughing,1 is a highly prevalent condition affecting up to 35% of women.2,3 Nonsurgical options such as behavioral therapy and pessaries are low-risk and low-cost interventions compared with surgical options for stress urinary incontinence, but there are less data about their effectiveness. Several clinical trials have shown that stress urinary incontinence symptoms improve when women are taught how to actively use their pelvic floor muscles to prevent urine loss.4–8 Likewise, continence pessaries have been successfully used to manage stress urinary incontinence,9–11 although few randomized trials exist on this modality.12,13 A recent multicenter randomized trial comparing the effectiveness of continence pessary with behavioral therapy with combined therapy (behavioral plus pessary), the Ambulatory Treatments for Leakage Associated With Stress incontinence study, showed that behavioral therapy resulted in greater patient satisfaction and fewer bothersome stress urinary incontinence symptoms compared with pessary at 3 months, the primary outcome time point, but these differences did not persist at 1 year.8
The ability to predict which patients with stress urinary incontinence will be successfully treated and satisfied with nonsurgical therapies would enhance patient counseling, with respect to both patient expectations of treatment and medical decision-making regarding treatment. Obesity, pelvic organ prolapse, severe stress urinary incontinence along with high psychological distress, and poor physical health were associated with a poor outcome after physical therapy for stress urinary incontinence in a study by Hendriks et al.14 In contrast, Theofrastus et al15 studied stress urinary incontinence symptoms after pelvic floor muscle training and could find no significant correlations with demographic variables, incontinence severity, or urodynamic measures. Although some conflicting data exist regarding predictors of success for behavioral therapy, information for continence pessaries is lacking.
The primary aim of this planned secondary analysis was to identify baseline factors that might predict treatment success and patient satisfaction in women undergoing nonsurgical therapy for stress urinary incontinence. Our secondary aim was to evaluate whether these factors differed among treatment approaches including the continence pessary, behavioral therapy, or combined therapy.
MATERIALS AND METHODS
The Ambulatory Treatments for Leakage Associated With Stress trial methods were previously reported.16 Briefly, adult women with symptoms of stress urinary incontinence were randomized to receive one of three nonsurgical interventions: continence pessary, behavioral therapy (pelvic floor muscle training and continence strategies), or combined therapy stratified by incontinence episode frequency (fewer than 14 compared with 14 or more incontinence episodes per week) and whether stress urinary incontinence only or stress predominant mixed urinary incontinence. Institutional Review Board approval was obtained at each site and the data coordinating center, and written informed consent was obtained from all participants. As in the primary analysis, the primary outcomes used to define success and satisfaction with therapy at 3 months were: the Patient Global Impression of Improvement and the stress incontinence subscale of the Pelvic Floor Distress Inventory. Treatment satisfaction was assessed with the Patient Satisfaction Questionnaire. For Patient Global Impression of Improvement, success was defined as a response of “much better” or “very much better” among responses on a 7-point Likert scale ranging from “very much worse” to “very much better.” For the stress incontinence subscale of the Pelvic Floor Distress Inventory (Urogenital Distress Inventory stress), success was defined as the absence of bothersome stress incontinence symptoms, ie, an answer of “no” to all six of the stress incontinence subscale items or a response of “yes,” but with a bother of “not at all” or “somewhat.” Patient Satisfaction Questionnaire was used to assess patient satisfaction with treatment, defined as “completely satisfied” or “somewhat satisfied” on a 4-point Likert scale. An intention-to-treat analysis was performed, including all individuals who were eligible and randomized to treatment. Participants who received any other treatment for incontinence and withdrawals were also considered randomized treatment failures.
Potential predictors for the primary outcomes and satisfaction included demographic variables (age, race, ethnicity, education, employment status), clinical variables (body mass index [calculated as weight (kg)/[height (m)]2], smoking status, alcohol usage, parity, medical comorbidity [with high comorbidity defined as two or more medical conditions and low comorbidity defined as fewer than two], menopausal status, estrogen status, hysterectomy, previous pelvic surgery, and previous treatment of pelvic organ prolapse), anatomic measures (Pelvic Organ Prolapse–Quantification measures Aa, Ap, Ba, Bp, genital hiatus (GH) with strain, and total vaginal length and Brink score), and quality of life measures (Short Form-36 mental composite summary score, Short Form-36 physical composite summary score), baseline Pelvic Organ Prolapse Distress Inventory and Pelvic Organ Prolapse Impact Questionnaire scores, as well as incontinence type and incontinence frequency by 7-day bladder diary, all measured at baseline.
Logistic regression was used to assess the relationship between potential predictors and each outcome. The model-building strategy to identify factors that might predict success and satisfaction outcomes included: 1) fit simple (univariable) logistic regression models for each potential predictor, 2) test for interaction of significant predictors with treatment approach to assess whether predictors of success and satisfaction differed by treatment, and 3) fit multivariable logistic regression to evaluate the effects of the predictors significant from the univariable logistic regression analyses with P<.05, adjusting for treatment, two stratification factors (incontinence type and incontinence frequency) and other important clinical covariates based on the literature, including age, Bp, GH with strain, and total vaginal length body mass index, Pelvic Organ Prolapse–Quantification stage, and hysterectomy (regardless of their significance in the simple regression model). Because of the high correlation (Pearson correlation coefficient more than 0.99; P<.001) between Ap and Bp, we only included Bp (the leading edge of the posterior wall) in the multivariable model. Analyses were performed using SAS 9.2, with statistical significance defined at 5%.
In the Ambulatory Treatments for Leakage Associated With Stress trial, 446 participants were randomly assigned to pessary (n=149), behavioral therapy (n=146), or combined therapy (n=151).8 One individual in the combined therapy group was found to be ineligible and was removed from subsequent analyses. Participants in the three treatment groups were similar in demographic and medical characteristics (Table 1). Overall, participants were on average 50 years of age, primarily white, and parous. Approximately 20%, by self-report, had attempted some nonsurgical therapy for their urinary leakage, although not in a controlled setting. Nearly half of participants reported stress-only symptoms and half reported stress-predominant mixed urinary incontinence symptoms and 55% of individuals reported fewer than 14 incontinence episodes per week.
The results of the univariable regression analysis of potential predictors of success (Patient Global Impression of Improvement, Urogenital Distress Inventory–stress) and satisfaction (Patient Satisfaction Questionnaire) measures at 3 months are demonstrated in Table 2. Race and menopausal status were associated with success as defined by the Patient Global Impression of Improvement; education status, previous urinary incontinence surgery, medical comorbidities, Pelvic Organ Prolapse Distress Inventory score, and incontinence frequency were associated with success as defined by the Urogenital Distress Inventory–stress subscale score. Pelvic Organ Prolapse–Quantification posterior wall points Ap, Bp, and GH with strain, and incontinence frequency were associated with success as defined by satisfaction. To identify whether predictors of success and satisfaction differed by treatment, we tested for interaction of treatment with the predictors that are significant in the bivariate analyses. None of the interactions was statistically significant (P≥.05; results not shown).
In the final multivariable regression models (Table 3), menopausal status remained a significant independent predictor of success as defined by the Patient Global Impression of Improvement, after controlling for treatment and other factors. Specifically, the odds of being successful 3 months after treatment for postmenopausal women were nearly 2.5-times the odds for premenopausal women (P=.03). Education and previous urinary incontinence surgery were significant predictors of success as defined by the Urogenital Distress Inventory–stress measure, after controlling for other predictors. The odds of success for college-educated women were approximately 1.5-times the odds for women with less than a college education (P=.04). Women who had not had previous urinary incontinence surgery had approximately three-times the odds of success compared with women who did have previous surgery (P=.04). Last, incontinence frequency predicted satisfaction after controlling for other predictors. The odds of being satisfied 3 months after treatment for women with fewer than 14 incontinence episodes per week at baseline were almost two-times the odds for women with 14 or more episodes (P=.01). Pelvic Organ Prolapse–Quantification points Bp and GH with strain were no longer significant in the multivariable regression model (P≥.05). These relationships were not affected by treatment.
The results of this planned secondary analysis of data suggest that there are certain factors for women pursuing nonsurgical therapy that increase the odds of treatment success and satisfaction. Women with fewer than 14 weekly urinary incontinence episodes were more likely to be satisfied than women who experienced more frequent urinary incontinence before intervention. This finding is similar to those of other investigators. Burgio et al17 reported that women who experienced more than 10 stress urinary incontinence episodes per week before intervention were less likely to achieve success (75% or more reduction of incontinence episodes recorded on bladder diary) after behavioral treatment including pelvic muscle exercises and continence strategies. Similarly, Hendriks et al14 identified severe stress urinary incontinence as one of 11 prognostic indicators of poor outcome (leakage severity and global perceived effectiveness) after physiotherapy for female stress urinary incontinence. Women who were college-educated were less likely to report symptom-related distress compared with women with less education. Hendriks et al14 also found women with lower education to have a poorer outcome related to leakage severity after a physiotherapy intervention for stress urinary incontinence. Education level has also been reported to effect outcomes after interventions for other medical conditions, such as chronic pain18 and lumbar disc herniation.19 Olson et al also found that education level affected outcomes, including bodily pain, physical function, and disability of persons who underwent nonsurgical interventions (physical therapy, education or counseling, home exercise, and nonsteroidal anti-inflammatory drugs) for lumbar disc herniation. Individuals with higher education attained better outcomes up to 4 years after nonsurgical intervention. Interestingly, outcomes of persons who received surgical intervention did not differ by education level.19 These investigators hypothesized that a difference in locus of control (the belief that one's health is contingent on one's own behavior) from external for surgical to internal for nonoperative interventions may explain why education level affected only those who underwent nonoperative interventions.20 Future studies should investigate this relationship and its effect on urinary incontinence intervention outcomes.
Women without previous urinary incontinence surgery were more likely to be successful based on stress symptoms as measured by the stress subscale of the Pelvic Floor Distress Inventory. This also has been noted in a previous study in which women who had undergone incontinence surgery before pessary use had a discontinuation rate higher than those women without previous surgery (72% compared with 27%, relative risk 1.62, 95% confidence interval 1.0–2.7). It was speculated that women with previous surgery may have had lower urethral closure pressures or lower urethral mobility, resulting in an altered urethral continence mechanism suboptimally managed with a pessary.9 Other investigators have noted that hysterectomy or other pelvic surgery predisposes to weakness of the pelvic floor, affecting the ability to optimally retain a pessary.21
Finally, postmenopausal women were more likely to report a greater global impression of improvement of their continence status than premenopausal women. This finding was surprising given the reported decline in muscle strength that occurs in postmenopausal women.22 However, in a recent literature review, Enns and Tiidus23 presented conflicting evidence regarding the effect of estrogen depletion on muscle structure (mass, size, or cross-sectional area) and function. These authors attributed this inconsistency to a number of factors, including the species examined, size and fiber-type composition of muscles examined, previous state of fitness of individuals, and the type and intensity of exercise protocols examined. Therefore, the decline in strength that occurs in older women may not be strictly attributed to hormone status. Other factors such as overall physical activity, exercise levels, and body weight may have a greater effect on muscle structure and function. Given the evidence, clinicians should be cautious to assume that age or menopause will limit a woman's ability to benefit from a trial of pelvic floor muscle exercise.
We found predictors of success to be the same for continence pessary, behavioral therapy, and the combination of the two. Previous studies of the continence pessary for stress urinary incontinence did not identify menopausal status, education, and incontinence severity as predictors of success; however, these were retrospective reviews.9,11 The randomized prospective design of our trial allows for a much better understanding of the influence of these factors, and we believe this can be beneficial to practitioners in deciding which patients might be candidates for a continence pessary or behavioral therapy or both.
The strengths of this study include its prospective design and robust follow-up in a large well-characterized population of women interested in conservative treatment for stress predominant urinary incontinence symptoms. Weaknesses include the relatively short-term follow-up of success and satisfaction outcomes and the potential lack of generalizability to community-based clinical populations as compared with academic practices. Despite these shortcomings, this information can be used to counsel women interested in conservative treatment for urinary incontinence. Further, adverse events are rarely seen in these two conservative treatment approaches; therefore, they should be considered for all women seeking care for urinary incontinence. Factors associated with longer-term nonsurgical treatment outcomes are also needed.
In summary, our findings have real implications for clinical care and future research and may help align physician and patient expectations of treatment benefit with more realistic goals. These results can be used to inform patients of their prognosis if interested in pursuing these two nonsurgical treatment modalities for stress predominant urinary incontinence symptoms. It does not mean that patients who do not meet these criteria will not obtain benefit from nonsurgical approaches for the management of stress urinary incontinence because there are other nonsurgical treatment modalities, including weight loss or the use of electrical stimulation. An individualized approach that balances available data and patient desires and needs continues to be a primary goal for optimized patient care.
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