Botox for overactive bladders: Predictors of treatment success

This study investigated whether certain patient characteristics affect treatment success with OnabotA (onabotulinumtoxin-A, botulinum toxin A, or Botox) for overactive bladders.

The researchers concluded that gender and symptom severity were reliable predictors of treatment success.

Bladder muscle over-activity is characterized by urinary urgency, and is often associated with urinary incontinence. OnabotA has been put forward as an effective alternative treatment option for patients that do not tolerate, cannot use, or do not respond to first-line drug therapy. OnabotA is injected directly into the bladder muscle, causing it to relax and reduce episodes of urinary incontinence. According to recent reports, OnabotA is not equally effective in all patients. This study examined whether there are certain markers that can predict treatment success of OnabotA, which could be valuable for pre-treatment consultation. 

89 patients with overactive bladders were included in the study. All patients received treatment with OnabotA. Treatment outcomes were followed for 6 months.

OnabotA injections were well-tolerated and no adverse effects were reported in this study. At three-month follow-up, treatment was successful in 64% of patients. Overactive bladder symptoms, episodes of urinary urgency, urgency severity, and urinary incontinence episodes were all improved, when compared to before treatment. Improvements in urinary symptoms were maintained at six months, though to a lesser degree.

Analysis showed that gender significantly affected treatment outcome. Women were nearly four times more likely to respond to treatment than men. Having urinary incontinence and less severe overactive bladder symptoms before the study were also predictors of high therapeutic effectivity. Patients with poor bladder emptying before treatment were consistently associated with incomplete bladder emptying, even after treatment with OnabotA.

The researchers concluded that the effects of OnabotA injections can benefit patient for up to six months. Female sex, urinary incontinence, and less severe overactive bladder symptoms are predictors of treatment success.

Larger clinical trials are needed to confirm these results. This study only included patients with demonstrated detrusor (bladder wall muscle) over-activity according to urodynamic testing, therefore results may not apply to all patient with overactive bladder symptoms.