Predictors of Acute Urinary Retention in Patients Undergoing Urethral Bulking

INTRODUCTION: Urethral bulking is a minimally invasive, office-based treatment for stress urinary incontinence (SUI). One of the most common adverse events following this procedure is acute urinary retention requiring temporary catheterization. The estimated rate of acute urinary retention following urethral bulking ranges from 0% to 20% (Hoe et al., 2021; Kirchin et al., 2017). To date, no studies have identified specific risk factors associated with an increased risk of urinary retention after urethral bulking. This knowledge could guide patient selection for urethral bulking and improve patient counseling. OBJECTIVE: To identify risk factors associated with the development of acute post-procedural urinary retention in patients undergoing urethral bulking. METHODS: This was an IRB-approved, retrospective cohort study of women undergoing urethral bulking for SUI at an academic medical center between January 2018 and December 2023. Eligible charts were identified using relevant CPT codes. Individuals with a preexisting reliance on an indwelling catheter or intermittent self-catheterization were excluded. Each medical record was reviewed to confirm that the designated procedure was performed and to ensure exclusion criteria were not met. All bulking agents were analyzed in aggregate. Patient demographics, medical comorbidities, and technical details were compared between patients who did and did not have acute urinary retention. Retention was defined as an inability to void immediately after or within 48 hours of the procedure, requiring catheterization. Mann-Whitney and Fisher’s exact tests were used for the analysis with a p<.05 considered significant. RESULTS: A total of 300 patients were included for analysis. 31 patients (10.3%) experienced acute urinary retention following urethral bulking. Table 1 summarizes the patient characteristics that were analyzed. Age, menstrual status, parity, and smoking status were not significantly different between the patients who retained and those who did not. Median BMI was significantly lower in the group that retained (p=0.015). The proportion of patients with diabetes, hypertension, or a neurologic condition did not differ by retention status. The proportion of patients who were taking anti-coagulation or overactive bladder medication at time of buking also did not differ by retention status. There was not a statistically significant difference in the proportion of patients who experienced retention for a top-up procedure compared to initial bulking (OR 0.507, p=0.202). Patients who received a peri-urethral block with lidocaine prior to bulking were significantly more likely to experience retention (OR 4.015, p=0.002). Notably, previous receipt of an anti-incontinence operation was associated with a lower risk of acute urination retention (OR 0.254, p=0.009). CONCLUSIONS: In this limited sample, the only patient characteristics associated with acute urinary retention following urethral bulking were lower BMI and lack of prior anti-incontinence surgery. The strongest association with acute urinary retention was the utilization of peri-urethral block. Larger studies are needed to assess if other technical aspects of urethral bulking are associated with increased risk of retention.