Purpose: Maintaining urinary continence at stress requires a competent urethral sphincter and good suburethral support. Sphincter competence is estimated by measuring the maximal urethral closure pressure at rest. We aimed to study the value of a new urodynamic measure, the urethral closure pressure at stress (s-UCP), in the diagnosis and severity of female stress urinary incontinence (SUI).
Methods: A total of 400 women without neurological disorders were included in this observational study. SUI was diagnosed using the International Continence Society definition, and severity was assessed using a validated French questionnaire, the Mesure du Handicap Urinaire. The perineal examination consisted of rating the strength of the levator ani muscle (0-5) and an assessment of bladder neck mobility using point Aa (cm). The urodynamic parameters were maximal urethral closure pressure at rest, s-UCP, Valsalva leak point pressure (cm H2O), and pressure transmission ratio (%).
Results: Of the women, 358 (89.5%) were diagnosed with SUI. The risk of SUI significantly increased as s-UCP decreased (odds ratio [OR], 0.92; 95% confidence interval, 0.88-0.98). The discriminative value of the measure was good for the diagnosis of SUI (area under curve>0.80). s-UCP values less than or equal to 20 cm H2O had a sensitivity of 73.1% and a specificity of 93.0% for predicting SUI. The association between s-UCP and SUI severity was also significant.
Conclusions: s-UCP is the most discriminative measure that has been identified for the diagnosis of SUI. It is strongly inversely correlated with the severity of SUI. It appears to be a specific SUI biomarker reflecting both urethral sphincter competence and urethral support.
Keywords: Bladder Neck Descent; Urethral Pressure; Urinary Incontinence, Stress; Urodynamics.