Mixed urinary incontinence (MUI) is a bothersome condition which combines symptoms of stress urinary incontinence (SUI) and urgency urinary incontinence (UUI).  The condition is problematic to treat and its prevalence increases with age. The BlueWind Medical Device, Revi®, is a commercially available, novel implantable tibial neuromodulation (iTNM) system to treat UUI.

The Overactive Bladder Stimulation System (OASIS) Study enrolled women with urgency-predominant urinary incontinence, however, many women presented with MUI. The aim of analysis was to understand the impact of iTNM in women with urgency predominant MUI on efficacy and quality-of-life (QoL) outcomes.

The OASIS Study was a prospective, multi-center, single arm pivotal study evaluating the safety and efficacy of the Revi System in adult females with UUI.  Inclusion criteria required >9 UUI episodes during a 7-day voiding diary (VD) and urgency predominant symptoms on the Medical, Epidemiology, and Social Aspects of Aging (MESA) questionnaire. VDs were collected at 1,3,6,9,12,18, and 24 months (mo) and the Overactive Bladder Questionnaire (OAB-q) was collected at 6,12, and 24mo.  

To assess the impact of the iTNM in women with MUI this post-hoc analysis compared those with no SUI on their baseline VD with those reporting at least one episode of SUI.

A total of 151 UUI patients underwent implantation. While all study participants had urgency predominant urinary incontinence, 41.1% (62/151) also presented with concomitant moderate to severe SUI symptoms on the MESA questionnaire (moderate SUI score: 10-18, severe SUI: 19-27). 

For this analysis, patients were grouped by baseline VD symptoms, a more commonly available measure than MESA scores; at baseline, 52 participants reported ≥ 1 episode of SUI, with an average of 0.41 episodes/day (median: 0.29 episodes/day). When comparing those without and without SUI at baseline, both groups had similar UUI episodes/day as well as similar baseline QoL scores (Table 1); those reporting at least one SUI episode also tended to have higher MESA SUI scores. 
Over follow-up, a similar UUI response rate was seen in both groups, with 70-80% of participants classified as “Responders” (≥50% reduction in UUI episodes) between 6 and 24m of treatment (Table 2). Importantly, similar improvements in QoL were observed, with both groups reporting changes in score well above the minimally important difference (MID: 10 points) of the OAB-q. At 6, 12, and 24m, the OAB-q score improved between 32.9-36.3 in patients with no episodes of SUI, and between 35.5-38.7 in participants with MUI (Table 2).

Women with MUI often respond less favorably to treatment (1), highlighting the need to further understand outcomes of minimally invasive therapies like iTNM in those with urgency-predominant MUI. This analysis supports the use of the Revi system in this population, showing similar reductions in UUI and improved quality of life to those with only UUI. Future analyses will examine whether iTNM reduced SUI episodes beyond urgency-related episodes.

Women with UUI symptoms frequently present with MUI. Those with urgency predominant MUI had similar efficacy and improvement in QoL over 2 years as those who had pure UUI symptoms. These results may give practitioners and patients additional confidence in choosing iTNM for bothersome UUI symptoms in the context of MUI.

Jha, S., Jeppson, P.C., Dokmeci, F. et al. Management of mixed urinary incontinence: IUGA committee opinion. Int Urogynecol J 35, 291–301 (2024). https://doi.org/10.1007/s00192-023-05694-z.