The primary treatment for urgency urinary incontinence (UUI) is anticholinergic medications. Injections of onabotulinumtoxinA (botulinum toxin) are effective in treating UUI resistant to anticholinergic therapy. However, this toxin can result in transient urinary retention, requiring temporary bladder catheterization. There have been no direct data comparing these 2 treatment methods.
This randomized, double-blind, double-placebo–controlled, randomized trial compared these 2 methods in women with idiopathic UUI. All subjects had 5 or more episodes of moderate-to-severe UUI per 3-day period, as recorded in a diary. An oral anticholinergic medication, solifenacin, was administered daily; a single injection of onabotulinumtoxinA was administered once daily as a single injection into the detrusor muscle. The effects of the 2 regimens were assessed over 6 months to determine the reduction in episodes of UUI, improvement in quality of life, and adverse effects.
Participants were randomly assigned to receive solifenacin at an initial daily dose of 5 mg for 6 months, with possible escalation to 10 mg, and if needed, switching to trospium XR, 60 mg, plus 1 intradetrusor injection of either saline or 100 U of onabotulinumtoxinA plus daily oral placebo. The primary study outcome was the reduction from baseline in mean episodes of UUI per day over the course of 6 months, as recorded in 3-day diaries submitted monthly. Secondary outcomes included complete resolution of UUI, quality of life, catheter use, and adverse events.
Data were available for primary outcome analysis for 241 of the 249 women who underwent randomization. Over the course of 6 months, the mean reduction in episodes of UUI per day was similar in the 2 groups, from 5.0 at baseline to 3.4 in the anticholinergic group and 3.3 in the onabotulinumtoxinA group (P = 0.81). Significantly more women in the onabotulinumtoxinA group than in the anticholinergic group reported complete resolution of UUI (27% vs 13%, P = 0.003). Both groups had improvements in the quality of life, with no significant between-group differences. Compared with the onabotulinumtoxinA group, the anticholinergic group had dry mouth more often (46% vs 31%, P = 0.02), but had lower rates of catheter use at 2 months (0% vs 5%, P = 0.01) and urinary tract infection (13% vs 33%, P < 0.001).
These findings show that oral anticholinergic therapy and onabotulinumtoxinA by injection are associated with similar reductions in the frequency of episodes of UUI and similar improvements in the quality of life. Patients treated with onabotulinumtoxinA, however, are more likely to have complete resolution of UUI and less likely to have dry mouth, but have a higher risk of transient urinary retention and urinary tract infection.