Correlation of urodynamic measures of urethral resistance with clinical measures of incontinence severity in women with pure genuine stress incontinence

OBJECTIVE: Our aim was to correlate multiple measures of urethral resistance with five clinical measures of incontinence severity in women with pure genuine stress incontinence. STUDY DESIGN: Seventy-five women with pure genuine stress incontinence underwent passive and dynamic urethral pressure profilometry and Valsalva leak point pressure determinations. The standardized and validated measures of incontinence severity included (1) the number of incontinent episodes, (2) the number of continence pads used recorded in a prospective 1-week urinary diary, (3) grams of fluid loss on a pad quantitation test, and (4) two condition-specific quality-of-life scales, the urogenital distress inventory and the incontinence impact questionnaire. The urodynamic and severity measures were compared with Pearson product-moment correlation analysis. RESULTS: There were no significant correlations betweendynamic urethral pressure profile pressure transmission ratios and any measure of incontinence severity. Passive urethral pressure profile variables correlated significantly with incontinence episodes and pad use. Valsalva leak point pressures correlated significantly with pad use and quantitation testing. None of the urodynamic measurements was significantly correlated with either of the quality-of-life scales, but our power to demonstrate a correlation was limited. CONCLUSIONS: Both passive urethral pressure profile measures and Valsalva leak point pressures correlate with some severity measures of genuine stress incontinence. Although inefficient pressure transmission during stress is critical to the pathogenesis of genuine stress incontinence, the severity of the pressure transmission defect is not related to clinical severity. Conversely, impairment of intrinsic urethral resistance is not essential to the pathogenesis of genuine stress incontinence, but the degree of sphincteric impairment is related to severity once the condition exists.