Prevalence of Urge Incontinence After Polyacrylamide Hydrogel Injection

Objectives: The objective of our study is to analyze urge urinary incontinence rates in patients with mixed urinary incontinence who underwent successful treatment for concurrent stress urinary incontinence with urethral polyacrylamide hydrogel injection.

Methods: All women older than 18 years old who underwent urethral polyacrylamide hydrogel injection between January 2021 to December 2023 at a single academic institution were retrospectively reviewed. All patients underwent urethral polyacrylamide hydrogel injection in an ambulatory surgery center. Only patients who had an ICD-10 diagnosis of mixed urinary incontinence (MUI) were included in the present study. Patients with concurrent neurogenic bladder or had received third line overactive bladder (OAB) therapy within the past year were excluded. Means and standard deviations were reported for continuous variables and proportions for nominal variables. Univariate analysis using Fisher exact test or chi-2 test for nominal variables and Mann-Whitney test for continuous variables were performed.

Results: Sixty-nine patients met inclusion criteria (n=69). Sixty-seven patients (97.1%) presented for their two week post-operative visit of which forty-two patients (62.7%) reported resolution of UUI. Fifty-nine patients (85.9%) presented for their six week post-operative visit of which twenty-nine patients (49.2%) reported resolution of UUI. Eight patients who had resolution of their UUI symptoms at two weeks reported recurrence of UUI at the six week visit (21.6% vs 78.4%, p< 0.0001). All twenty-five patients who reported continued UUI at two weeks, reported persistence at six week visit (p < 0.0001). Twenty-nine patients (43.3%) ultimately underwent treatment of their OAB symptoms after urethral polyacrylamide hydrogel injection.

Conclusions: Urethral polyacrylamide hydrogel may provide some benefit to UUI in those with MUI. However, this benefit may be temporary given a recurrence rate of approximately 22% at six weeks postoperative and a large number of patients undergoing subsequent treatment for OAB symptoms. Nonetheless, reassessment of UUI after urethral polyacrylamide hydrogel injection may be beneficial to guide subsequent treatment. Ultimately, further prospective and randomized study is required to further elucidate the mechanisms of urethral polyacrylamide hydrogel injection on UUI.