Systematic Review: Randomized, Controlled Trials of Nonsurgical Treatments for Urinary Incontinence in Women

Prevalence estimates of urinary incontinence vary according to the definition and the method of data collection (113). In general, urinary incontinence affects about 19% of women age 19 to 44 years, 25% of those age 45 to 64 years, and 30% of those age 65 years and older. About 18% of younger women (19 to 44 years of age) (14) and 28% of women older than age 65 years (15) experience daily urinary incontinence, whereas 30% of women older than age 65 years (8, 1620) and 27% of middle-aged women (17, 18, 21) report severe urinary incontinence. The severity of incontinence influences quality of life and treatment decisions (22, 23). Clinical interventions to reduce urinary incontinence (2434) have been extensively reviewed by the Cochrane Collaboration, the International Consultation on Incontinence (22, 23, 35), and the Agency for Healthcare Research and Quality (36, 37). Most studies examined short-term curative effects of treatment in participants with urinary incontinence. The basis for measuring successful treatment varied across the studies that examined different interventions. The present review synthesizes evidence on the effectiveness of nonsurgical clinical interventions to treat urinary incontinence in community-dwelling women. This review was commissioned as background material for a National Institutes of Health Office of the Medical Applications of Research State of the Science Conference on Prevention of Fecal and Urinary Incontinence. The full report can be found at www.ahrq. gov/downloads/pub/evidence/pdf/fuiad/fuiad.pdf. Methods Data Sources We identified studies from MEDLINE (via PubMed), CINAHL, Cochrane databases, and manual searches of reference lists from systematic reviews and the proceedings of the International Continence Society (Appendix Table 1). Study Selection Two investigators independently decided on study eligibility according to recommendations from the Cochrane Handbook for Systematic Reviews of Interventions (38) to include original publications of randomized, controlled trials (RCTs) that were published in English from 1990 to May 2007. Full texts of the RCTs that examined the effects of nonsurgical clinical interventions on urinary incontinence in community-dwelling women were eligible for the review. We excluded secondary data analyses, case reports, case series, and RCTs that did not report patient outcomes. We also excluded RCTs that analyzed surrogate outcomes of subjective and objective measures of severity of urinary incontinence, including continuous changes in the number of incontinence episodes or pad use, and urodynamic variables. We excluded, but further assessed for selection bias, 17 RCTs published before 1990, 2 RCTs conducted in nursing home residents (39, 40), and 2 RCTs that examined long-term indwelling catheters or bed pads (41, 42). One study of eligible medications was analyzed in the Cochrane review (43) and is included in our present analysis (44). Several RCTs examined drugs that were not eligible for our review (4547). We concluded that we did not omit clinically important, relevant information by restricting our review to articles published from 1990 to May 2007. The information about all outcomes can be found in the full-text report, available at www.ahrq. gov/downloads/pub/evidence/pdf/fuiad/fuiad.pdf. Data Extraction and Quality Assessment Two researchers abstracted the data by using standardized forms that elicited information about study samples, interventions, designs, and outcomes. Study quality was analyzed by using the following criteria: participant selection, length and loss of follow-up, use of intention-to-treat principle, masking of the treatment status, randomization scheme, adequacy of randomization and allocation concealment, and justification of sample sizes (evidence tables can be found at www.ahrq.gov/clinic and in Appendix Tables 2 and 4 to 10) (48). We used the Grading of Recommendations Assessment, Development and Evaluation working group definitions to evaluate the overall strength of the evidence as high, moderate, low, very low, or insufficient (49, 50). The number of events, including prevalence of urinary incontinence, improvement of urinary incontinence, and continence after interventions in the active treatment and control groups, was abstracted to calculate relative risk and risk difference with 95% CIs among randomly assigned women; the intention-to-treat principle was applied (51, 52). The number of events among treatment groups was calculated from the reported rates among randomly assigned or analyzed women for intention-to-treat analysis. Baseline data were compared in the studies to test differences in the target population and unusual patterns in the data (53, 54). Errors in data extractions were assessed by comparing the established ranges for each variable and the data charts with the original articles. Reproducibility of the results was confirmed by repeating the calculations with different models. The analytic framework for the systematic review and meta-analyses was created according to the Quality of Reporting of Meta-Analyses statement (55). Applicability of the population was estimated by evaluating the inclusion of women in clinical trials (56). Applicability of the intervention duration was high for studies with a follow-up of 1 year or more and was acceptable for studies with a follow-up of 6 to 12 months. We used several strategies to reduce bias, including a comprehensive literature search of published and unpublished evidence in several databases, a search of reference lists of systematic reviews and proceedings of the International Continence Society, and contacts with experts for additional references. Data Synthesis and Statistical Analysis We report clinical definitions of urinary incontinence as they were used by the authors of the original studies and with calculated rates of continence and improvement for purposes of comparison: the number of participants continent after the clinical interventions, the number of participants with improvement in severity of urinary incontinence, and the number of participants with prevalent cases of urinary incontinence. We defined long-term (>6 months' duration at follow-up) continence as a primary outcome for the present review because continence is the better-defined and most important clinical outcome. In contrast, definitions of urinary incontinence and improvement in urinary incontinence included presence as well as frequency and severity of symptoms. The rates of continence could not always be interpreted as the reciprocal of the rates of incontinence if trials reported only cases of urinary incontinence but excluded cases of improved urinary incontinence. The efficacy of clinical interventions was analyzed from the trials that compared active treatments with placebo, regular care, or no active treatments. The comparative effectiveness of the interventions was analyzed from the trials with active controls, long-term follow-up, adequate sample size, and intention-to-treat analysis (57). Pooling criteria included RCTs that reported outcomes after the same clinical interventions (58). Meta-analysis was used to assess the consistency of the association between treatments and urinary incontinence outcomes with random-effects models (59). Consistency in results was tested by comparing the direction and strength of the association. Chi-square tests and I 2 tests were used to assess heterogeneity in study resultsa P value less than 0.01 and an I 2 value greater than 50% were considered high (60, 61). We conducted meta-regression analyses by using the dose of the drug tested in individual RCTs (62). We could not perform formal meta-analyses for all treatments and outcomes because of methodologic diversity among the trials and different measurements and definitions of the outcomes. The absolute risk difference in rates of outcomes in the active and control groups was calculated for each study and in pooled analysis (63, 64). To permit the studies with zero events in one group to have the correct CIs (65, 66), we used 0.5 zero-cell correction (65) and compared the results of Peto, MantelHaenszel, and DerSimonian and Laird random-effects and fixed-effects method summary estimates (65, 66). Calculations were performed by using STATA software (STATA, College Station, Texas) at a 95% CI (63). Role of the Funding Source The Agency for Healthcare Research and Quality suggested the initial questions and provided copyright release for this manuscript but did not participate in the literature search, data analysis, or interpretation of the results. Results Of 248 RCTs on urinary incontinence interventions, we included 96 that examined nonsurgical treatments in women and reported patient outcomes (Figure 1). The Table shows evidence grades and a summary of the comparative conclusions. The studies included women with mixed urinary incontinence, predominant symptoms of stress urinary incontinence (6778), urodynamic stress urinary incontinence (7987), predominant urge urinary incontinence (88), overactive bladder with urge urinary incontinence (8994), or minimal urinary incontinence (9597) (Appendix Tables 2 and 4 to 10). The studies did not explicitly exclude women with other types of urinary incontinence; therefore, the effects of the treatments can be applied to women with mixed urinary incontinence. Figure 1. Study flow diagram. PFMT = pelvic floor muscle training; UI = urinary incontinence. *Literature search was conducted to examine diagnosis of, prevalence of, incidence of, risk factors for, and clinical interventions for UI and fecal incontinence. Some randomized, controlled trials examined several interventions. Table. Evidence of the Comparative Effectiveness of Clinical Interventions on Urinary Incontinence in Community-Dwelling Women Urinary continence after various interventions was defined as self-reported ability to control urination according to voiding diaries