Measurement of urethral closure function in women with stress urinary incontinence

PURPOSE: We assessed the use of urethral pressure reflectometry in detecting pressure increases in the female urethra and compared the usefulness of urethral pressure reflectometry vs urethral pressure profilometry in a pharmacodynamic intervention study.

MATERIALS AND METHODS: In this randomized, double-blind, placebo controlled, crossover study 17 women with stress urinary incontinence or mixed urinary incontinence received 4 mg esreboxetine or placebo for 7 to 9 days followed by a washout period before crossing over treatments. Urethral pressure reflectometry and urethral pressure profilometry were performed before and at the end of each treatment period.

RESULTS: The urethral opening pressure measured with urethral pressure reflectometry increased significantly compared to placebo by 13.7 cm H(2)O (p <0.0001) with an observed within subject standard deviation of 5.4. The increase in maximum urethral closure pressure was 8.4 cm H(2)O compared to placebo (p = 0.06) and for maximum urethral pressure the increase was 9.9 cm H(2)O (p = 0.04). However, the within subject SD for these parameters was higher at 11.4 and 12.2, respectively, implying lower power for these analyses. While receiving esreboxetine patients had significantly fewer incontinence episodes and reported a treatment benefit (global impression of change) compared to placebo.

CONCLUSIONS: The opening pressure measured with urethral pressure reflectometry was less variable compared to the parameters measured with urethral pressure profilometry (maximum urethral closure pressure and maximum urethral pressure). Consequently using urethral pressure reflectometry would result in a more efficient study design when investigating pharmacological effects on the urethra in future studies. We also found that esreboxetine was well tolerated, and had a positive and clinically relevant effect on urethral closure function and symptoms of stress urinary incontinence.