Construction and Validation of a Nomogram for Diagnosis of Female Stress Urinary Incontinence Combined with Anatomic/Intrinsic Urethral Sphincter Deficiency

Background: In order to improve the diagnostic accuracy of anatomical/intrinsic sphincter deficiency (ISD) in female patients with stress urinary incontinence (SUI) and to provide a reference for surgical approaches, we developed a nomogram model based on urodynamic parameters. Methods: Clinical data from 1150 women with complicated SUI treated at the Department of Urology, Third Xiangya Hospital, Central South University (01/01/2017– 10/30/2023) were retrospectively analyzed. Patients were randomly divided into a training cohort (805 cases, 70%) and a validation cohort (345 cases, 30%). ISD was diagnosed by maximum urethral closure pressure (MUCP < 30 cmH 2 O) or Valsalva leak point pressure (VLPP ≤ 60 cmH 2 O). Independent predictors of ISD were identified in the training cohort using binary logistic regression to construct the nomogram, validated using the validation cohort. Results: Multivariate analysis identified abdominal pressure to urinate, IBPM, voiding time, urethral closure pressure, MUCP, and VLPP as independent predictors of ISD. The nomogram demonstrated good discrimination: training cohort AUC = 0.8308 (95% CI: 0.8022– 0.8604); validation cohort AUC = 0.8408 (95% CI: 0.7964– 0.8844). Decision curve analysis (DCA) indicated significant clinical benefit for both cohorts. Conclusion: This urodynamic parameter-based nomogram (incorporating abdominal pressure to urinate, IBPM, voiding time, urethral closure pressure, MUCP, and VLPP) provides higher diagnostic accuracy for identifying anatomical/structural differences (ISD) in women with complicated SUI compared to traditional criteria (MUCP < 30 cmH 2 O or VLPP ≤ 60 cmH 2 O), providing important references for the selection of surgical approaches. Keywords: stress urinary incontinence, SUI, intrinsic sphincter deficiency, ISD, nomogram