The Utility of Simple Cystometry

Despite its common use, there is limited contemporary evidence regarding the place of simple cystometry (SC) in the evaluation of urinary function.

Our objective was to assess the accuracy of SC with respect to complex urodynamic study (UDS), evaluate the correlation between them, and determine whether performing both tests on the same patient offers any additional benefit.

In this retrospective cohort study, 609 consecutive women aged >18 years who underwent both UDS and SC within the same 6-month period between January 1, 2017, and December 31, 2022, were evaluated at a tertiary academic center. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of SC were evaluated for detecting stress urinary incontinence (SUI) and detrusor overactivity (DO), using UDS as the gold standard. Pearson correlation for filling parameters was calculated. Each patient served as their own control for each test.

There was a weak correlation between SC and UDS for first sensation ( r =0.30), first urge ( r =0.38), and maximum cystometric capacity (MCC) ( r =0.43). SC detected DO with a sensitivity of 38% (28-48%) and a specificity of 86% (82-89%). SC detected SUI with a sensitivity of 79% (75-83%) and a specificity of 53% (46-60%). When UDS was performed in conjunction with SC, an additional 14% of patients (n=87) were found to have SUI.

The correlation between SC and UDS with respect to filling phase parameters is low. SC testing demonstrated a high sensitivity for SUI and a high specificity for DO. The combination of SC and UDS may enhance SUI detection rates.