A randomized trial of urodynamic testing before stress-incontinence surgery

Abstract

Background: Urodynamic studies are commonly performed in women before surgery for stress urinary incontinence, but there is no good evidence that they improve outcomes.

Methods: We performed a multicenter, randomized, noninferiority trial involving women with uncomplicated, demonstrable stress urinary incontinence to compare outcomes after preoperative office evaluation and urodynamic tests or evaluation only. The primary outcome was treatment success at 12 months, defined as a reduction in the score on the Urogenital Distress Inventory of 70% or more and a response of "much better" or "very much better" on the Patient Global Impression of Improvement. The predetermined noninferiority margin was 11 percentage points.

Results: A total of 630 women were randomly assigned to undergo office evaluation with urodynamic tests or evaluation only (315 per group); the proportion in whom treatment was successful was 76.9% in the urodynamic-testing group versus 77.2% in the evaluation-only group (difference, -0.3 percentage points; 95% confidence interval, -7.5 to 6.9), which was consistent with noninferiority. There were no significant between-group differences in secondary measures of incontinence severity, quality of life, patient satisfaction, rates of positive provocative stress tests, voiding dysfunction, or adverse events. Women who underwent urodynamic tests were significantly less likely to receive a diagnosis of overactive bladder and more likely to receive a diagnosis of voiding-phase dysfunction, but these changes did not lead to significant between-group differences in treatment selection or outcomes.

Conclusions: For women with uncomplicated, demonstrable stress urinary incontinence, preoperative office evaluation alone was not inferior to evaluation with urodynamic testing for outcomes at 1 year. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and the Eunice Kennedy Shriver National Institute of Child Health and Human Development; ClinicalTrials.gov number, NCT00803959.).

Figure 1. Study Enrollment

The major reasons for not meeting the inclusion criteria were not meeting the definition of stress-predominant urinary incontinence (1032 women), having prolapse (639), or having a history of surgery for incontinence or other conditions (528). Reasons for declining to participate were related to study procedures (e.g., too invasive or requiring too much time; 164 women), randomization (210), or insurance coverage (5). Administrative reasons included a delay in starting the study (e.g., because of delayed approval by the institutional review board; 114 women), no staff members at the study site who were certified in the patient’s native language (43), and other reasons (156). Of the 40 women who provided informed consent but were deemed ineligible before randomization occurred, 10 withdrew consent (3 were not available to start treatment within 6 weeks after randomization, 1 did not have data for the provocative stress test, and 6 had other reasons), 11 had data from urodynamic studies reviewed in the previous 12 months, 7 did not have data for the provocative stress test, 5 were not available to start treatment within 6 weeks after randomization, and 7 had other reasons. Of the 11 women who withdrew consent after random assignment to urodynamic testing, 5 did not complete the testing and were not included in the per-protocol analysis. Of the 27 women lost to follow-up, 1 did not have stress urinary incontinence (according to the MESA questionnaire) and 2 did not complete urodynamic testing; these women were not included in the per-protocol analysis.

Figure 2. Primary Outcome Results

Success was defined as a reduction of at least 70% in the Urogenital Distress Inventory score from baseline to 12 months and a response of “very much better” or “much better” on the Patient Global Impression of Improvement measure at 12 months. The horizontal I bars indicate 95% confidence intervals. The dashed vertical line denotes the predetermined noninferiority margin of 11 percentage points.