Posterior Tibial Nerve Stimulation With versus Without Mirabegron: A Randomized Controlled Trial

Introduction and Hypothesis To compare change in urgency urinary incontinence episodes (UUIEs) in women undergoing posterior tibial nerve stimulation (PTNS) plus mirabegron versus PTNS plus placebo for the treatment of refractory urgency urinary incontinence (UUI).

The primary hypothesis was that combination therapy is superior to monotherapy.

Methods A randomized controlled trial was performed in individuals identifying as female aged ≥ 18 years with UUI symptoms refractory to second-line treatment or who could not tolerate antimuscarinic medications.

Both participants and providers were blinded to medication treatment allocation.

Participants were randomized (1:1) to PTNS plus mirabegron or PTNS plus placebo.

Participants completed a 3-day bladder diary prior to and after 12-week treatment.

Validated symptom distress and impact questionnaires were obtained pre- and post-treatment.

The primary outcome was change in mean number of UUIEs on a 3-day bladder diary pre- versus post-treatment between arms.

Primary and secondary outcomes were analyzed via sample t tests.

Results Fifty-four subjects were randomized, mean ± SD baseline age 56.2±15.6 years and body mass index 35.0±9.4 (kg/m^2); no differences were noted in any clinical–demographic characteristics.

There was a significant difference between arms in mean pre- to post-treatment UUIEs, 9.4±3.9, mirabegron versus 5.3±5.5, placebo ( p =0.007).

Significant differences were found pre- compared with post-treatment in urinary frequency, Overactive Bladder Questionnaire Short Form Symptom Bother and Symptom Health-Related Quality of Life scores.

Conclusions In subjects undergoing PTNS treatment for refractory UUI and OAB-wet symptoms, the addition of a β-3 agonist produced significant improvement in both objective and subjective overactive bladder symptom outcomes compared with PTNS plus placebo.