Transcutaneous Tibial Nerve Stimulation for Urgency Urinary Incontinence

Objectives: Transcutaneous tibial nerve stimulation (TTNS) has been proposed as a home-based, patient-centered therapy that could improve access to care for women with overactive bladder. The primary objective of this study was to determine the efficacy of TTNS in reducing symptomatic bother among ambulatory women with urgency urinary incontinence (UUI) as compared to a sham intervention.

Methods: This was a double-masked, sham-controlled randomized trial conducted at a single center. Women with UUI were eligible if they demonstrated at least 6 episodes of UUI on a 3-day voiding diary and had not previously undergone posterior tibial nerve stimulation, OnabotulinumtoxinA injection, or sacral neuromodulation. Enrolled women were then randomized to receive either TTNS or sham therapy for 12 weeks (Figure 1). Study interventions were self-administered by participants twice weekly. The primary outcome was the change in Overactive Bladder Questionnaire (OAB-q) scores compared between groups. Secondary outcomes included the proportion of women who achieved a 50% or greater reduction in UUI episodes as reported on a 3-day voiding diary and participants’ perceived improvement measured by the Patient Global Impression of Improvement questionnaire (PGI-I). An intention-to-treat analysis was performed. Continuous variables were analyzed using an independent samples t-test. For dichotomous variables, Pearson’s chi-squared test was used.

Results: One hundred women were randomized (65 intervention, 35 sham) and included in analysis (Figure 2). Both groups experienced improvement in OAB-q symptom severity and health-related quality of life sub scale scores as well as the number of UUI episodes post-intervention as compared to baseline. Comparison of the magnitude of change in OAB-q sores between groups showed no significant difference for either sub scale (P=0.5-1). A sensitivity analysis was performed in which the missing primary outcome data from 7 participants were classified as all “successes” versus all “failures.” The results of these analyses showed no difference in OAB-q scores between groups (P=0.7-1). In the TTNS group, 58.8% of women reported a 50% or greater reduction in UUI episodes on their voiding diaries versus 41.7% of women in the sham group (P=0.2). On the PGI-I, 51.7% of women in the TTNS group reported some degree of improvement versus 45.5% in the sham group (P=0.5). In the TTNS group, 38.1% of participants guessed their randomization allocation. In the sham group, 73.5% identified the correct group.

Conclusions: In conclusion, TTNS does not appear to be more effective than sham therapy in reducing symptomatic bother from UUI. An observed placebo effect, which is consistent across overactive bladder studies, suggests therapeutic benefit from establishing medical care and regularly connecting with a medical practitioner. These elements should be considered when developing new therapies for overactive bladder and UUI.