Adverse events of intravesical botulinum toxin a injections for idiopathic detrusor overactivity: risk factors and influence on treatment outcome.

BACKGROUND: Intravesical injection of botulinum toxin type A (BoNTA) provides effective treatment for detrusor overactivity and overactive bladder (OAB). However, the high rates of treatment-related adverse events (AEs) prevent its more widespread use.

OBJECTIVE: To investigate the risk factors of increasing AEs after BoNTA injection for idiopathic detrusor overactivity (IDO).

DESIGN, SETTING, AND PARTICIPANTS: This study included a total of 217 patients receiving their first intravesical BoNTA injection for refractory IDO in a tertiary university hospital from 2004 to 2009.

MEASUREMENTS: AE incidence was analyzed according to gender, age, comorbidities, prostate condition in men, OAB subtype, BoNTA dose, injection site, and baseline urodynamic parameters. Successful outcome was determined based on patient perception of improvement of bladder condition at 3 mo.

RESULTS AND LIMITATIONS: Successful outcomes were reported by 144 (66.3%) patients. By multivariable analysis, male gender (p=0.013) and baseline postvoid residual (PVR) ≥100ml (p=0.003) were independent predictors of acute urinary retention (AUR). Baseline PVR ≥100ml (p=0.007) and receiving >100 U BoNTA (p=0.029) were predictors of straining to void. The incidence of large PVR after treatment was associated with comorbidity (p=0.011). Urinary tract infection occurred more frequently in women (p=0.003) and in men with retaining prostate (p=0.008). No AUR developed after bladder base/trigonal injection. Nevertheless, the occurrence of AUR or large PVR did not affect therapeutic outcome. This study is limited by nonconsecutive enrollment of patients.

CONCLUSIONS: Male gender, baseline PVR ≥100ml, comorbidity, and BoNTA dose >100 U are risk factors for increasing incidence of AEs after intravesical BoNTA injection for IDO.