Urodynamics, the supine empty bladder stress test, and incontinence severity

Abstract

Determine whether urodynamic measures of urethral function [(valsalva leak point pressure (VLPP), maximum urethral closure pressure (MUCP), functional urethral length (FUL)] and the results of the supine empty bladder stress test (SEBST) correlate with each other and with subjective and objective measures of urinary incontinence (UI). Data were collected preoperatively from subjects enrolled in a multicenter surgical trial of mid-urethral slings. Subjective measures included questionnaire scores from the Medical Epidemiological and Social Aspects of Aging Questionnaire, Urogenital Distress Inventory, and Incontinence Impact Questionnaire. Objective measures included a 24-hr pad weight test, incontinence episode frequency on a 3-day voiding diary, and a SEBST. Five hundred ninety-seven women enrolled. Three hundred seventy-two women had valid VLPP values; 539 had valid MUCP/FUL values. Subjective measures of severity had weak to moderate correlation with each other (r = 0.25-0.43) and with objective measures of severity (r = -0.06 to 0.45). VLPP and MUCP had moderate correlation with each other (r = 0.36, P< 0.001). Urodynamic measures of urethral function had little or no correlation with subjective or objective measures of severity. Subjects with a positive SEBST had more subjective and objective severity measures compared to the negative SEBST group, but they did not have significantly different VLPP and MUCP values. VLPP and MUCP have moderate correlation with each other, but each had little or no correlation with subjective or objective measures of severity or with the results of the SEBST. This data suggests that the urodynamic measures of urethral function are not related to subjective or objective measures of UI severity.