Effectiveness of BTX-A and neuromodulation in treating OAB with or without detrusor overactivity: a systematic review

Patients with refractory overactive bladder (OAB) pose a therapeutic challenge. Guidelines such as those from the National Institute for Health and Care Excellence recommend invasive treatments such as botulinum toxin-A ((BTX-A), sacral neural stimulation (SNS) etc. only if there is detrusor overactivity (DO) on urodynamics.

Our aim was to systematically evaluate evidence based on the presence or absence of DO in relation to differences in effectiveness and complications related to invasive treatment in patients with refractory OAB. We carried out a systematic search of Cochrane, MEDLINE, Embase, CINAHL, LILACS, meta-Register of Controlled Trials (mRCT), CENTRAL, and Google Scholar databases from inception until April 2016. Abstracts presented at IUGA, ICS and EAU conferences (until April 2016) were included and journals that were hand searched.

We found five studies (two prospective cohort studies and subgroup analyses of two randomized controlled trials (RCTs) and one cohort study for BTX-A, one multicenter prospective cohort study for percutaneous tibial nerve stimulation (PTNS) and three (one RCT and two cohort studies) for SNS. The outcomes in patients without (n = 77) or with (n = 135) DO were similar in the context of urodynamic findings, bladder diaries, quality of life (QoL) questionnaires, etc. when treated with BTX-A [odds ratio (OR) 1.52, 95% confidence interval (CI) 0.40-5.77] or SNS (50 patients without and 81 with DO; OR1.37, CI 0.76-2.48). Outcomes for PTNS (based on a single study) seem to be better in patients without DO.

The limited evidence suggests that urodynamic diagnosis of DO does not alter patient reported outcomes for invasive treatments such as BTX-A and SNS. Noninferiority RCTs powered to evaluate the role of DO in predicting treatment response are required.