Botulinum toxin-A injections for idiopathic overactive bladder: a systematic review and meta-analysis

To review the current evidence on the efficacy and safety of botulinum toxin-A in the management of idiopathic overactive bladder (OAB).

A systematic search of PubMed, Embase and the Cochrane Central Search Library was performed. All randomized controlled trials comparing botulinum toxin-A with placebo, different doses and injection techniques, in patients with idiopathic OAB was included. The analyzed outcomes were quantification of symptoms, urodynamic outcomes, quality of life and adverse events.

A total of 1,020 participants from 12 randomized controlled trials were included. Botulinum toxin-A was associated with less urinary frequency, less incontinence episodes, improvement in quality of life, higher post-void residual-related catheterization and higher urinary tract infection. Doses of 100-300 U were not consistently differentiated from each other in voiding diary, quality of life and urge urinary incontinence. No statistically significant difference was seen between bladder body and bladder base, bladder body and bladder body plus trigone in urinary retention and urinary tract infection.

Botulinum toxin-A is associated with significant improvement in OAB symptoms in patients with idiopathic OAB. However, there is a higher incidence of postoperative urinary retention and urinary infection compared to placebo. Low-dose botulinum toxin-A seems to be the optimum dose that appropriately balances the benefits with adverse events. Trigone inclusion seems as safe and effective as trigone-sparing injection.