Urinary incontinence (UI) is highly prevalent in nursing and residential care home (CH) residents and associated with high personal, social, physical and economic burden. UI treatment options are limited in this care context and predominantly rely on containment using expensive and undignified absorbent products. Transcutaneous posterior tibial nerve stimulation (TPTNS) is a non-invasive, safe and low-cost intervention with promising evidence of effectiveness for reducing UI in adults [1], including older women [2]. The ELECTRIC trial aimed to compare the clinical effectiveness of TPTNS and sham stimulation to reduce the volume of UI in CH residents.

A multicentre, pragmatic, parallel group randomised controlled trial compared 24-hour volume of UI leaked in CH residents receiving TPTNS or sham electrical stimulation at 6 weeks. Trial recruitment took place between Jan 2018 and Aug 2019 in 37 nursing and residential CHs in Scotland and England. Eligible residents had weekly or more UI, wore absorbent pads and used a toilet/toilet aid for bladder emptying, with or without assistance. Excluded residents had an indwelling urinary catheter, post void residual urine (PVRU) volumes >300 ml, a cardiac pacemaker, bilateral leg ulcers, treated epilepsy, pelvic cancers or were non-English speaking. 
Residents were randomised (1:1) via remote computer allocation, stratified by sex, severity of UI and care home centre. CH staff were trained to deliver a 6-week programme of 12 x 30 min stimulations to all participants using two surface electrodes and an electrical stimulator. The TPTNS group received 30 minutes’ continuous stimulation to the tibial nerve (behind medial malleolus) at the highest tolerable intensity, 10 Hz frequency, pulse width 200µs-1 twice weekly for 6 weeks. Those in the sham group received identical stimulation but at a low intensity (4 mA) stimulation and delivered above the lateral malleolus, to avoid the tibial nerve. 
The primary outcome was the volume of urine leaked in a 24-hour period measured by pad weight test (PWT) at 6 weeks post randomisation. Secondary outcomes were the volume of UI leaked over a 24-hr period at 12 and 18 weeks; the number of absorbent pads used in 24-hrs at 6, 12 and 18 weeks; resident, staff, and family perceptions of bladder condition; toileting skills and quality of life.
Intention-to-treat analysis was undertaken, with participants’ data analysed according to their randomised group. Group differences in UI volume leaked at 6 weeks were assessed using a linear mixed model adjusting for stratification variables, UI severity, gender and baseline UI leakage, with CH centre as a random effect. Secondary outcomes were analysed using similar generalised linear models. A sample size of 278 residents randomised allowed detection of a 200 ml difference in the primary outcome with 90% power, but to account for potential differences in variability and missingness of data, the target recruitment was 400 residents.

406 residents were randomised from 37 CHs: 197 residents to TPTNS group and 209 to sham stimulation. Resident mean age was 85.5 years (SD 8.1) and 77.6% were female. The mean Mini Mental State Examination Score (MMSE) was 13.1 (SD 9.1) indicating moderate dementia and 76.6% of the 252 residents with a MMSE score were in the moderate or severe dementia category. The mean Barthel score was 7.6 (SD 3.9) demonstrating the high physical dependency and more than half (52%) were severely frail with 27% moderately frail. UI in 233 (57.2%) was severe (>400 ml/24 hours) and for the whole sample the mean total urine leakage was 573 ml (SD 442). The mean 24-hour pad use was 3.4 (SD 1.7).
Primary outcome data were available for 344 residents (166 TPTNS and 178 sham stimulation). Table 1 shows there was no significant difference between the groups in the 24-hour volume of urine leaked at 6 weeks post randomisation (primary outcome time point) or at 12 or 18 weeks’ post-randomisation. 
Sub-group analysis showed no significant effects of TPTNS at the primary outcome time point: there was no significant difference between groups by sex, severity of UI; physical dependence; mobility levels; toilet use dependence; clinical frailty; use of anticholinergic medication; or falls status. 
There were no significant differences in secondary outcomes between the groups at 6-weeks for the number of absorbent pads used in 24 hours, resident quality of life, resident perception of bladder condition or family perception of bladder condition. However, there was a significant difference in staff assessment of residents’ toileting skills [TPTNS mean score 14.2 (SD 6.8); sham mean score 12.5 (SD 7.4); mean difference 1.23 (95% CI 0.22 to 2.24; p = 0.017)]. The staff perception of resident bladder condition was significantly better for the TPTNS group than the sham group [TPTNS mean score 2.9 (SD 1.4); sham mean score 3.2 (SD 1.4); mean difference -0.51 (95% CI -0.96 to -0.07; p = 0.024)]. The 12-week and 18-week secondary outcomes showed no significant differences between the TPTNS and sham groups for the number of absorbent pads used in 24-hours, resident quality of life, resident, family or staff perception of resident’s bladder condition. There was a significant difference in staff assessment of residents’ toileting skills at 18 weeks [TPTNS mean score 15.6 (SD 6.0); sham mean score 13.7 (SD 6.8); mean difference 1.24 (95% CI 0.16 to 2.33; p = 0.024)].

In this sample of very elderly, physically and mentally frail nursing and residential care home residents, we found no evidence that TPTNS effectively reduced the volume of urine leaked in 24-hours, compared to sham stimulation.

In care home residents TPTNS is no more effective than sham stimulation at reducing volume of UI. Investigation of the potential role of care home contextual factors to explain the result should be undertaken.

Booth J, Connelly L, Dickson S, Duncan F, Lawrence M. The effectiveness of transcutaneous tibial nerve stimulation (TTNS) for adults with overactive bladder syndrome: A systematic review. Neurourology and Urodynamics. 2018 Feb;37(2):528-541. doi: 10.1002/nau.23351. Epub 2017 Jul 21.
Schreiner L, Santos T, Knorst M. Randomised trial of transcutaneous tibial nerve stimulation to treat urge urinary incontinence in older women. Int Urogynecol J. 2010; 21:1065–1070.