(Poster 60) Post-void Residual: Utility in the Evaluation of Lower Urinary Tract Symptoms

Objectives: The objective was to determine if there are any clinical predictors for elevated post-void residual (PVR) in patients with lower urinary tract symptoms (LUTS). Measurement of PVR is currently recommended by every national urologic and urogynecologic organization, though the level of evidence is poor. The 2023 AUA/SUFU Guideline for OAB states “may obtain PVR”; AUA/SUFU guideline 2023 for surgical treatment of SUI recommends “assessment of PVR”; AUGS practice bulletin on urinary incontinence in women 2015 “minimal evaluation is to measure PVR”; SUFU/AUGS/ICS guideline on female stress incontinence 2024 states “PVR should be documented preop” all with level of evidence as clinical principle. The diagnostic rationale is that the PVR can provide clinicians with a comprehensive understanding of the patient’s bladder functionality, and its association with symptoms which can lead to an evidence-based diagnosis and directed therapy. Unfortunately, the most accurate measurement of PVR is straight catheterization which is uncomfortable and invasive.

Methods: This was a quality improvement study. Data from new patients presenting with LUTS evaluated by fellowship trained urogynecologists at a single academic center from August 2012 to May 2023 were extracted from the medical record. Those with interstitial cystitis, chronic pelvic pain, and recurrent UTI were excluded. Patients were divided into two groups based on age: 1) > 70 years and 2) < 70 years. Our primary outcome was elevated PVR defined as > 100 ml. Demographic and clinically related information was compared between the two groups. Non-normal continuous variables were analyzed using Kruskal-Wallis test, other continuous variables by t-test, and categorical variables were analyzed using Chi Square. Multivariable logistic regression analysis was performed to examine elevated PVR risk among patients.

Results: Of the 1,665 new patients who were reviewed and analyzed, 416 (25%) were > 70 years of age and 1,249 (75%) < 70 years of age. There were 65/416 (16%) who had a PVR > 100 ml in the > 70 years cohort, compared to 138/1,249 (11%) in the < 70 years cohort, p =0.01. In a multivariable logistic regression analysis, when controlling for age, race, BMI, smoking history, history of back surgery, prolapse, OAB, stress incontinence, OAB medication use, history of hysterectomy, diabetes, urinalysis, and neurologic disorders, only history of prior prolapse or anti-incontinence surgery was associated with a PVR > 100 (aOR 2.82 [1.75, 4.56], p < 0.01).

Conclusions: Patients > 70 years of age were more likely to have an elevated PVR. However, when controlling for other factors, only a history of a prior prolapse or anti-incontinence surgery was associated with PVR > 100 ml. Based on these preliminary results it may be reasonable to consider a PVR assessment for patients who have had a prior prolapse or anti-incontinence surgery and not a universal application.