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.