Purpose: We evaluated the use of botulinum toxin-A in treating patients with idiopathic detrusor overactivity refractory to anticholinergics.
Materials and methods: This double-blind, placebo controlled trial randomized participants to intradetrusor injections of 200 U botulinum toxin-A (16 patients) or placebo (18 patients). The primary outcome measure was change in maximum cystometric capacity. Secondary outcome measures included changes in overactive bladder symptoms, post-void residual, maximum detrusor pressure during filling cystometry and reflex detrusor volume. Quality of life was assessed using the Incontinence Impact Questionnaire short form 7 and Urogenital Distress Inventory short form 6. Followup occurred at 4 and 12 weeks after injection, at which point the study was unblinded. Further followup in the botulinum toxin-A group occurred at 24 weeks.
Results: Significant increases in maximum cystometric capacity were observed at 4 weeks (difference 144.69 ml, 95% CI 100.95 to 215.75, p <0.0001) and 12 weeks (difference 95.71 ml, 95% CI 47.47 to 172.45, p = 0.001) in patients treated with botulinum toxin-A compared to placebo. Botulinum toxin-A reduced frequency (p <0.001, p = 0.003) and urgency urinary incontinence (p = 0.03, p = 0.008) episodes at 4 and 12 weeks, respectively. Urgency was reduced at 4 weeks (p = 0.005) in the botulinum toxin-A group. In patients receiving botulinum toxin-A, post-void residual increased at 4 weeks (p = 0.024) but became insignificant by 12 weeks (p = 0.406). Of these patients 6 required intermittent self-catheterization. Significant improvements in quality of life were observed following botulinum toxin-A. The extension study suggests that the beneficial effects of botulinum toxin-A are maintained for at least 24 weeks.
Conclusions: Botulinum toxin-A at 200 U is safe and effective for idiopathic detrusor overactivity and the beneficial effects persist for at least 24 weeks.