Reduction of urgency severity is associated with long-term therapeutic effect after intravesical onabotulinumtoxin A injection for idiopathic detrusor overactivity.

AIMS: Intravesical onabotulinumtoxin A (BoNT-A) injection is a promising treatment for refractory detrusor overactivity (DO). This study investigated the long-term success rate of BoNT-A injection for patients with idiopathic DO and its association with reduction of urgency severity.

METHODS: This study was a retrospective analysis of 174 patients with idiopathic DO who received first-time 100  U BoNT-A injections. The patients were collected from several previous clinical trials. The therapeutic effects were classified as significant sensory effects with urgency severity score reductions of ≥2 and/or significant motor effects with cystometric bladder capacity increases of ≥25%. The treatment results based on patients' perceptions of bladder conditions and long-term success rates were analyzed among the different therapeutic-effect subgroups.

RESULTS: A successful outcome was reported by 138 (79.3%) patients at 3 months. Seventy-seven (44.3%) patients had both sensory and motor effects, 5 (2.9%) had sensory effects alone, 83 (47.7%) had motor effects alone, and 9 (5.2%) had no sensory or motor effect. All 82 patients with sensory with/without motor effects reported a successful result. In contrast, only 50 (60.2%) patients with motor effects alone reported success at 3 months. Increased cystometric bladder capacity and postvoid residual and decreased voiding efficiency were noted in patients with motor with/without sensory effects. The therapeutic results lasted significantly longer in patients with sensory with/without motor effects than those with motor effects alone.

CONCLUSIONS: Improvement of urgency severity is significantly associated with a higher success rate at 3 months and longer therapeutic duration after intravesical BoNT-A injection for IDO.