Login to Access Video or Poster Abstract: MP31-16
Sources of Funding: This study was sponsored by Medtronic

Introduction

This analysis aims to describe the use of concomitant overactive bladder (OAB) medications following implant of the sacral neuromodulation (SNM) InterStim® system. Subjects with bothersome symptoms of OAB including urinary urge incontinence (UI) or urgency-frequency (UF), who had not exhausted all medication options (failed at least 1 anticholinergic medication and had at least 1 medication not tried) were included in the InSite study.

Methods

Subjects were restricted from taking OAB medications for the first 6 months post-implant. Concomitant use of OAB medications was allowed after 6 months. At each visit, data were collected on OAB medications used since previous visit. The number of implanted subjects who used any concomitant OAB medication post-implant is summarized by medication type. Baseline characteristics were compared between implanted subjects with and without concomitant OAB medication use during any time between implant and 5-years follow-up. Logistic regression was used to assess the effect of concomitant OAB medication use on 5-year therapeutic success in UI and UF subjects respectively.

Results

Of 272 subjects that were implanted, 91% were female and the mean age was 57 years. A total of 73 subjects used any concomitant OAB medications between 6 months and 5 years post implant; the most commonly used medications were mirabegron, oxybutynin, and solifenacin. At baseline, subjects qualified more frequently as both UI and UF in the group with concomitant OAB medication use vs. the group with no concomitant OAB medication (54% vs. 44%, p=0.0479), and subjects with concomitant OAB medication use were older (mean age of 60.5 vs 55.6, p=0.0163). When assessing the effect of concomitant OAB medications use on therapeutic response with baseline characteristics and test stimulation response adjusted, UI subjects were less likely to have 5-year therapeutic success if they had concomitant OAB medication use compared to those who didn't (Odds Ratio=0.28, 95% Confidence Interval 0.10-0.80, p=0.0171). No relationship between concomitant OAB medication use and UF therapeutic response was observed.

Conclusions

This result shows that a small portion of subjects implanted with InterStim use concomitant OAB medications post implant. However, the presence of OAB medications after implant does not improve long term therapeutic success. In UI subjects, the association between concomitant OAB medication use and poorer long term therapeutic success might indicate that a subset of subjects with symptoms remain refractory even with addition of OAB medications.

Funding

This study was sponsored by Medtronic