The Effects of Age, Gender, and Postvoid Residual Volume on Catheterization Rates After Treatment with OnabotulinumtoxinA for Overactive Bladder

Background: Transient increases in postvoid residual urine volume (PVR) requiring clean intermittent catheterization (CIC) have occurred with onabotulinumtoxinA treatment for overactive bladder (OAB).

Objective: To evaluate onabotulinumtoxinA safety and the effect of age, gender, and maximum PVR (PVR_max) on CIC initiation in adults with OAB and urinary incontinence (UI).

Design setting and participants: This was a pooled post hoc analysis of four placebo-controlled, multicenter randomized trials that included adults with idiopathic OAB after first onabotulinumtoxinA treatment (NCT00910845, NCT00910520, NCT01767519, NCT01945489). Patients had at least three urgency UI episodes over 3 d and at least eight micturitions per day, had inadequate management with at least one anticholinergic agent, and were willing to use CIC.

Outcome measurements and statistical analysis: We measured the following outcomes: PVR_max within 12 wk after first treatment; CIC incidence; estimated functional capacity; PVR ratio (PVR/estimated functional capacity).

Results and limitations: Of 1504 patients, 87.7% were women and 88.8% were White. The mean age was 60.5 yr across 10-yr age groups, baseline PVR was 13.8-35.0 ml, and estimated functional capacity was 293.5-475.7 ml. Mean baseline PVR was 21.3 ml overall versus 34.0 ml in the group that started CIC. The CIC incidence was 6.2% for women (range 1.1-8.4%) and 10.5% for men (range 0-14.6%). Higher CIC rates were observed for PVR_max >350 ml (women 91.9%, men 84.6%) in comparison to PVR_max of 201-350 ml (women 32.5%, men 17.4%) and PVR_max <200 ml (women 1.2%, men 1.6%). Overall, 2/1504 patients (both women) were unable to void spontaneously. The mean PVR ratio was highest at week 2. Some subgroups had small sample sizes.

Conclusions: CIC incidence was low overall, was less frequent for women, was rare with PVR_max ≤200 ml, and did not appear to correlate with baseline PVR.

Patient summary: After onabotulinumtoxinA treatment for OAB, patients sometimes insert a catheter to help in emptying their bladder after urinating. In this study, few patients needed a catheter, especially when less urine volume remained after urination.