Indirect treatment comparison (ITC) of medical therapies for an overactive bladder

Overactive bladder syndrome (OAB) is a chronic and prevalent condition which has a negative impact on Quality of Life. The National Institute of Clinical Excellence issued two documents which give slightly varying algorithms of pharmacotherapy for OAB, offering mirabegron as a possible treatment in certain circumstances. In the absence of trials involving a direct comparison of therapies, an indirect comparison can provide useful information on the difference in treatment effects between competing interventions.

To compare effectiveness of available medical therapies for OAB using Bucher indirect treatment comparison (ITC) model.

A systematic literature search identified randomised controlled trials (RCT) assessing effectiveness of drugs for OAB versus placebo. Then indirect comparisons of the treatments effects were made, preserving the randomisation of the originally assigned patient groups, using Bucher method.

25 RCTs met inclusion criteria. In keeping with ITC method validity, four assessments were undertaken of mirabegron against anticholinergics, which were number of incontinence episodes, micturition episodes, urgency episodes in 24 h and volume of micturition. This indirect treatment analysis suggests that mirabegron is as effective as anticholinergics in managing of OAB, except for solifenacin which appears to be superior.

These findings suggest that work looking into treatment choice should be individualized to patient characteristics rather than fitting patients to a treatment. Further work is required to identify what patient characteristics may be crucial and indicate that studies exploring the most effective sequence of managing treatment naïve patients and those with refractory disease.