Real-World Retention Rates After Intravesical OnabotulinumtoxinA for Idiopathic Overactive Bladder.

INTRODUCTION: The risk of incomplete bladder evacuation requiring catheterization after intravesical onabotulinumtoxinA (BoNT-A) is well established. However, the rates reported in the literature are highly variable and low overall in clinical trials. We attempt to evaluate the rate of symptomatic acute urinary retention requiring catheterization after initial BoNT-A in a private practice setting of patients with idiopathic overactive bladder.

METHODS: We performed a retrospective study from 2010 to 2014 for patients with idiopathic overactive bladder undergoing their first BoNT-A. Demographic information recorded included age, sex, presence of diabetes, baseline postvoid residual (PVR), presence of urodynamic detrusor overactivity, bladder capacity, peak flow rate (Qmax), BoNT-A unit dose, and carrier volume. Urinary retention was defined as those patients who were symptomatic and required catheterization for a PVR of 200 mL or greater.

RESULTS: Of 103 patients who received BoNT-A, 21 (20.3%) developed symptomatic retention requiring catheterization. There was no difference in baseline characteristics, preoperative PVR, and units injected (all P > 0.05). The retention group had a higher rate of bacteriuria and symptomatic urinary tract infection (all P < 0.05). Despite developing symptomatic retention requiring performance of catheterization, 47% of these patients continued with a subsequent injection of BoNT-A.

CONCLUSIONS: The need for catheterization after initial delivery of intravescial BoNT-A is an adverse event that seems to be higher in our clinical practice than seen in clinical trials. This information will be critical in order to properly counsel our future patients about the risks and benefits of this therapy.