Botulinum toxin injection has small but uncertain clinical benefit when compared to sacral neuromodulation for refractory incontinence

Authors noted that while the difference was statistically significant, it had uncertain clinical importance, and patients who received injections were more likely to develop urinary tract infections and to need transient self-catheterization.


OnabotulinumtoxinA injections yielded small but clinically uncertain benefit for refractory urinary incontinence in women compared with sacral neuromodulation, according to a new study.

Researchers performed an open-label randomized trial at 9 U.S. medical centers from February 2012 to January 2015 to evaluate whether onabotulinumtoxinA injections outperformed sacral neuromodulation in women who had refractory urgency urinary incontinence. All sites were participating in the Pelvic Floor Disorders Network, sponsored by the National Institutes of Health. Patients who had recorded a minimum of 6 urgency incontinence episodes in a baseline 3-day diary were assigned to receive 200 U of onabotulinumtoxinA via cystoscopic intradetrusor injection or sacral neuromodulation.

The study's primary outcome was change from baseline to 6 months in mean daily urgency urinary incontinence episodes, as measured by patients' 3-day diaries. Secondary outcomes were adverse events; change from baseline in urinary symptom scores on the Overactive Bladder Questionnaire Short Form, which ranges from 0 to 100, with higher scores denoting worse symptoms; and change in baseline in urinary symptom scores on the Overactive Bladder Satisfaction questionnaire, which ranges from 0 to 100, with higher scores on 5 subscales indicating better satisfaction. The study results were published in the Oct. 4 JAMA.

One hundred ninety-two women were assigned to the injection group, and 189 were assigned to the sacral neuromodulation group. The intention-to-treat population included 364 women, 190 in the injection group and 174 in the sacral neuromodulation group. In this population, the injection group had a larger reduction in mean episodes of urgency incontinence per day at 6 months than the sacral neuromodulation group (−3.9 vs−3.3; mean difference, 0.63; P=0.01). Those who received injections also had more improvement in symptom bother (P=0.002), treatment satisfaction (P=0.01), and treatment endorsement on the Overactive Bladder Satisfaction Short Form questionnaire (P<0.001).

No between-group differences were noted for convenience, adverse events, or treatment preference; however, urinary tract infections were more common in the injection group (35% vs. 11%; risk difference, −23% [95% CI, −33% to −13%; P<0.001). Six women (3%) in the sacral neuromodulation group had device revision or removal during the 6-month study period, and in the injection group, 8%, 4%, and 2% needed intermittent self-catheterization at 1, 3, and 6 months, respectively.

The authors noted that they tested a single injection of 1 type of botulinum A toxin and that the trial compared 2 active treatments, which meant that they could not evaluate a placebo effect. They concluded that in women with refractory urgency urinary incontinence, onabotulinumtoxinA yielded small daily improvement in incontinence episodes versus sacral neuromodulation. However, they said, while the difference was statistically significant, it had uncertain clinical importance, and patients who received injections were more likely to develop urinary tract infections and to need transient self-catheterization. “Overall, these findings make it uncertain whether onabotulinumtoxinA provides a clinically important net benefit compared with sacral neuromodulation,” the authors wrote.