There were 122 women allocated to the botox treatment group and 118 women allocated to the placebo group.
The researchers compared the outcomes in the botox and placebo groups at the six-month follow-up. They found that in any 24-hour period women in the botox group:
emptied their bladders less often: 8.33 times versus 9.67 times, a difference of 1.34 (95% confidence interval [CI] 1.00 to 2.33, p=0.0001)
experienced fewer leakage episodes: 1.67 versus 6.00, a difference of 4.33 episodes (95% CI 3.33 to 5.67, p<0.0001)
experienced fewer episodes of urgency to urinate: 3.83 versus 6.33, a difference of 2.50 episodes (95% CI 1.33 to 3.33, p<0.0001)
Almost a one-third of women in the botox group (31.3%) developed bladder control (or continence) following their treatment, compared to 12.0% in the placebo group (Odds Ratio [OR] 3.12, 95% CI 1.49 to 6.52, p=0.002).
However, urinary tract infection was reported at least once during six months by a one-third of women in the botox treatment group, compared to 10% in the placebo group (OR 3.68, 95% CI 1.72 to 8.25, p=0.0003).
Those given botox also reported greater difficulty emptying their bladders, which required self-catheterisation to remove their urine: 16% of the botox group compared to 4% of the placebo group (OR 4.87, 95% CI 1.52 to 20.33, p=0.003).