Monday March 12 2012
Botox can ease incontinence by freezing bladder muscles
Botox injections may help women with urinary incontinence, The Daily Telegraph has today reported. The newspaper said that injecting the muscle-freezing toxin into the wall of the bladder can have a long-lasting impact on overactive bladder syndrome, a major cause of incontinence.
The newspaper’s story is based on a UK medical trial that investigated whether the paralysing properties of botox were effective at reducing the symptoms such as frequently using the toilet, feeling an urgent need to urinate, and leakage in patients with overactive bladder syndrome.
The trial featured 240 women who had not responded to medical treatments for overactive balder syndrome. The researchers found that women who received the botox injection experienced these symptoms significantly less frequently than women who received a dummy injection of saltwater. However, women given botox were more likely to get urinary tract infections.
The results of the study indicate that botox may be effective in treating a common and upsetting health condition. However, if it does get adopted into use in this way there are several other treatment options (including lifestyle measures, bladder training exercises and medication that would be considered first. Botox may be considered as an option only if these treatments fail, and the benefits would have to be considered in relation to its potential harms.
Where did the story come from?
The study was carried out by researchers from the University of Leicester and was funded by the Moulton Charitable Trust and the women’s health charity Wellbeing of Women.
The study was published in the peer-reviewed medical journal European Urology.
The Telegraph covered this study appropriately, covering the study size and design, as well as the treatment benefits and harms.
What kind of research was this?
While it is hard to gauge the true scale of the problem, research suggests that around 13% of women in the UK may have some form of urinary incontinence. Although many conditions and factors can cause urinary incontinence, one major cause is overactive bladder syndrome. The condition is marked by uncontrolled contraction of the bladder that results in an urgent need to pass urine. While this can lead women to need the toilet frequently, some also experience a form of leakage called urge incontinence.
An overactive bladder can be a cause of urge incontinence, which is when urine leaks at the same time or just after you feel an intense urge to pass urine. Urge incontinence differs from stress incontinence, where the pelvic floor muscles are too weak to prevent urination. This causes urine to leak when your bladder is placed under pressure from actions such as coughing or laughing.
This was a placebo-controlled randomised controlled trial that examined the effectiveness and safety of using botulinum toxin (botox) as a treatment for overactive bladder syndrome. A randomised controlled trial is the best way to measure the effectiveness of a treatment, as the randomisation process helps to ensure that any patient characteristics that may influence the outcome have an equal chance of appearing in either treatment group. This allows researchers to be confident that any observed effect is due to the treatment under study.
What did the research involve?
The researchers enrolled 240 women with bladder muscle overactivity, or overactive bladder syndrome, that had not responded to previous treatment. The women were randomly allocated injections of either Botulinum toxin A (botox) or placebo (saltwater) into the wall of the bladder. Women with another common type of incontinence, stress incontinence, were not included in the study.
The participants kept a diary over three days, recording the number of times they:
- emptied their bladder
- felt an urgent need to empty their bladder
- experienced an unintentional passing of urine (or leakage)
The women also completed a questionnaire that assessed their quality of life, as overactive bladder syndrome often has a significant negative impact on patient quality of life.
The researchers conducted follow-up sessions with the women on average at six weeks, three months and six months after treatment. They assessed differences in the frequency of the above three symptoms between the two treatment groups. They also compared quality of life scores, treatment complications and time until troubling symptoms returned between the two groups.
The researchers used appropriate statistical methods to assess differences in frequency of symptoms between the two groups.
What were the basic results?
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).
How did the researchers interpret the results?
The researchers concluded that injections of botulinum toxin A into the bladder wall is an effective and safe treatment for overactive bladder syndrome in women who have not responded to previous treatment.
Urinary incontinence can be a distressing and problematic condition, and although we cannot be sure of the number of people affected, research suggests it is surprisingly common.
While there is a range of potential treatments and ways to manage urinary incontinence (including medication, bladder training, lifestyle changes and surgery) not all people respond to them, and they can have problems. This randomised controlled trial provided good evidence that botox injections may be a useful treatment option for women with incontinence due to overactive bladder syndrome that has proven difficult to treat with other methods.
The researchers say that the relief of symptoms reported by the participants was considerably better than those who used oral anticholinergic drugs. These drugs act on the nerve supply to the bladder and are the standard medical treatment used for this condition. They add that other randomised controlled trials have reported similar effects.
The researchers say that since they designed their trial, other studies have published results that support using a lower recommended dose of botox for this type of treatment. Therefore, it is unclear if the same results would be found at this reduced dose. They also say that their study recruited participants with severe cases of overactive bladder syndrome, and that it is unclear if the treatment would be as effective in less severe cases.
It is important to note that the study participants did not have stress incontinence, which is a common cause of urinary incontinence. Therefore, the results of this study cannot be generalised to all women with symptoms of overactive bladder or incontinence, but can only be applied to those with diagnosed overactive bladder syndrome (or detrusor overactivity).
Botox is not routinely used by the NHS in this way, but if it were then it would probably be considered as an option only among women who have required specialist referral for their condition. This would be given after they had tried other treatment options first, which may include lifestyle measures and bladder training exercises in addition to oral medications. If these treatments fail, the benefits of botox would have to be considered in relation to its potential harms.