Urinary retention rates after intravesical onabotulinumtoxinA injection for idiopathic overactive bladder in clinical practice and predictors of this outcome.

AIMS

The purpose of this study was to find the rate of urinary retention in clinical practice after treatment with onabotulinumtoxinA (BTN/A) for refractory overactive bladder (OAB) symptoms and determine factors that predict this outcome.

METHODS

This is a retrospective study of BTN/A for treatment of non-neurogenic, refractory OAB symptoms. Patients were analyzed with respect to their first and second BTN/A injections. The primary outcome measure was postoperative urinary retention. Statistical significance was assessed with multivariate logistic regression.

RESULTS

Based on inclusion and exclusion criteria, the study population was 160. Mean age was 64 ± 13.2 years and 24% of the patients were men. The rate of urinary retention was 35% (n = 56). For the first BTN/A treatment, multivariate analysis revealed that preoperative PVR (post-void residual volume) (OR 1.27, 95% CI 1.13-1.43, P < 0.001) and preoperative bladder capacity (OR 1.05, 95% CI 1.01-1.08, P = 0.005) were associated with postoperative urinary retention. In patients with a preoperative PVR of ≥100 ml, 94% (n = 17) went into urinary retention. For those who underwent a second BTN/A treatment, preoperative PVR, BTN/A units injected and retention after the first BTN/A were associated with an increased rate of postoperative retention.

CONCLUSIONS

Increased preoperative PVR was associated with urinary retention. The retention rate is higher than that reported in recent clinical trials. The inclusion of patients with a preoperative PVR ≥100 ml and a lower threshold to initiate clean intermittent catheterization contributed to this high rate of retention.