Cost consequence analysis of transcutaneous tibial nerve stimulation (TTNS) for urinary incontinence in care home residents alongside a randomised controlled trial

Abstract

Background

Urinary incontinence (UI) is prevalent in more than half of residents of nursing and residential care homes and can have a detrimental impact on dignity and quality of life. Care homes predominantly use absorbent pads to contain UI rather than actively treat the condition. Transcutaneous tibial nerve stimulation (TTNS) is a non-invasive, safe, low-cost intervention with demonstrated effectiveness for reducing UI in adults. We examined the costs and consequences of delivering TTNS to care home residents in comparison to sham (inactive) electrical stimulation.

Methods

A cost consequence analysis approach was used to assemble and present the resource use and outcome data for the ELECTRIC trial which randomised 406 residents with UI from 37 care homes in the United Kingdom to receive 12 sessions of 30 min of either TTNS or sham (inactive) TTNS. TTNS was administered by care home staff over 6 weeks. Health state utility was measured using DEMQOL-U and DEMQOL-PROXY-U at baseline, 6 weeks and 18 weeks follow-up. Staff completed a resource use questionnaire at baseline, 6 weeks and 18 weeks follow-up, which also assessed use of absorbent pads.

Results

HRQoL did not change significantly in either randomised group. Delivery of TTNS was estimated to cost £81.20 per participant, plus training and support costs of £121.03 per staff member. 85% of participants needed toilet assistance as routine, on average requiring one or two staff members to be involved 4 or 5 times in each 24 h. Daily use of mobility aids and other assistive devices to use the toilet were reported. The value of staff time to assist residents to use the toilet (assuming an average of 5 min per resident per visit) was estimated as £19.17 (SD 13.22) for TTNS and £17.30 (SD 13.33) for sham (per resident in a 24-hour period).

Conclusions

Use of TTNS to treat UI in care home residents did not lead to changes in resource use, particularly any reduction in the use of absorbent pads and no cost benefits for TTNS were shown. Managing continence in care homes is labour intensive, requiring both high levels of staff time and use of equipment aids.

Trial registration

ISRCTN98415244, registered 25/04/2018. NCT03248362 (Clinical trial.gov number), registered 14/08//2017.

Background

Urinary incontinence (UI) is a distressing condition for older adults that negatively impacts their dignity and quality of life [1]. With the number of individuals affected by UI predicted to increase rapidly as the population ages, the cost of treating and managing UI is also set to increase [2]. However there is a lack of information about the economic costs of treating UI: a review of 86 trials of anticholinergic drugs prescribed for incontinence noted that no costs or economic measures had been reported in any of the included trials [3]. The highest prevalence of UI is found in older adults living in nursing and residential care homes [4]. More than half of care home residents are estimated to be living with UI [5]. Care homes predominantly use absorbent pads to contain UI rather than actively treat the condition [6]. The NHS currently spends upwards of £80 million a year on absorbent pads alone for the purpose of containing UI [5]. This excludes the costs of associated care needed to manage their use in older frailer individuals or those living with dementia. One potential active intervention for UI is transcutaneous tibial nerve stimulation (TTNS), which uses low frequency electrical stimulation applied to the ankle in a programme of 12 half hour sessions, to stimulate the nerves controlling bladder sensation and reduce symptoms of urgency to void [7]. TTNS is a non-invasive, safe intervention with potential effectiveness for reducing UI in older adults [8]. However, there is little evidence regarding cost-effectiveness of TTNS and although a few studies have reported costs for non-surgical treatments for UI these did not involve TTNS [9,10,11].

The ELECtric Tibial nerve stimulation to Reduce Incontinence in Care Homes (ELECTRIC) trial was a multicentre, sham stimulation controlled randomised trial to compare effectiveness of TTNS with sham stimulation to reduce volume of UI in care home residents [12, 13]. In addition, a longitudinal, mixed methods process evaluation explored acceptability of the intervention as well as intervention delivery fidelity and support. A published protocol [12] and full trial report [13] are available. Thirty-seven care homes (nursing and residential) in England and Scotland took part. Alongside the trial an economic evaluation compared TTNS to sham (inactive) electrical stimulation. This article reports the results of a Cost Consequence Analysis (CCA) which examined the costs of providing TTNS for frail older residents in care homes, changes in resource use in each trial group over time, and assessed the impact on health-related quality of life (HRQoL). Data about HRQoL was measured using DEMQOL and DEMQOL-PROXY, outcome measures designed specifically for use with individuals experiencing cognitive decline and dementia [14, 15]. DEMQOL-U consists of five domains: positive emotion, memory, relationship, negative emotion, loneliness. There are four possible levels of response relating to severity available. DEMQOL-PROXY-U consists of four domains (as DEMQOL-U but without loneliness domain) and has four response levels. The original intention was to use the DEMQOL and DEMQOL-PROXY for cost-effectiveness analysis (CEA) to complement the CCA. However, as no significant difference in primary outcomes or outcomes used for cost-effectiveness were observed, it was decided that it was inappropriate to continue to produce incremental cost-effectiveness ratios between the two groups. For the economic analysis the assumption was made that the sham stimulation group represented usual continence care (excluding the sham stimulation). Baseline data was used to establish the usual continence care pathways in care homes in terms of resource use patterns. The aim of the analysis was to estimate the costs and consequences of TTNS in care homes, summarising the resource use and outcome data in a CCA balance sheet.

Methods

Participants and setting

Participants in this study were from the ELECTRIC trial: 25/04/2018, ISRCTN98415244 and ClinicalTrials.gov NCT03248362 14/08/2017. A CONSORT diagram can be found in the full NHS Health Technology Assessment (HTA) report available online [13], and a copy is provided as a supplementary material (Additional file 1). Participants were older adults residing in care homes, including those with cognitive impairment, who experienced UI at least weekly, used the toilet or a toilet-aid for bladder emptying, with or without assistance, and wore absorbent pads to contain urine. Residents were not eligible if they had an indwelling urinary catheter; symptomatic urinary tract infection; post-void residual urine volume more than 300ml; a cardiac pacemaker; treated epilepsy; bilateral leg ulcers; current pelvic cancer; palliative care status, or were non-English speakers.

TTNS intervention

Participants received an electrical stimulation programme comprising 12 sessions of 30 minutes’ duration each. Delivered twice weekly over 6 weeks using a portable machine (Neurotrac Continence™), two surface electrodes were applied to the ankle to electrically stimulate the tibial nerve. Delivery of each session required one care home staff member to attach and set up the machine, and remove it once treatment was complete. Continual presence of staff members was not required during the stimulation session. Each staff member received a specific package of training to deliver TTNS, including a handbook and DVD and ongoing support by an Implementation Support Facilitator, if needed.

Economic evaluation

An economic evaluation of TTNS compared with usual continence care was completed in the form of a CCA [16] and results were presented in a CCA balance sheet. Descriptive presentation of the array of effects of the intervention enables decision makers to form their own opinion on relevance and relative importance of the findings to their decision making context [17]. Outcomes, such as use of incontinence products or impacts on continence care pathways, were reported in natural units. Costs were reported in GBP 2018–2019 prices. Discounting was not required. To provide a practical assessment of resource implications and consequences of interest for those involved in care home service provision and making funding decisions a public sector payer (central government Treasury) perspective was used.

Data collection

Baseline demographic data was collected in the main trial and included age, gender, UI severity, need for help to use the toilet. Individual resident absorbent pad usage in 24 h (brand, product name, size and number used) was measured at baseline, 6, 12 and 18 weeks using diaries kept by care home staff which were counted by the Research Assistants. The staff grade of the person delivering TTNS or sham stimulation and average time taken to set up and remove equipment (over 6 week period (minutes) was recorded by trained care home staff. Participant HRQoL was measured using DEMQOL and DEMQOL-PROXY (titled DEMQOL-Carer) questionnaires at baseline, 6 and 18 weeks [14, 15]. Raw scores were converted to a single utility index for DEMQOL-U and for DEMQOL-PROXY-U using the scoring algorithm for the UK [18, 19]. A Resource Use Questionnaire (RUQ) designed for this study was used to collect data about resources required for toilet assistance, aids and devices for managing incontinence, medication prescribed for overactive bladder symptoms and incontinence, and use of primary care. The RUQ was administered at baseline to establish the usual continence care pathway and completed by a Research Assistant. Data about appointments with health services staff for continence problems were available at 6 weeks and 18 weeks (each covering the preceding 6 weeks).

Unit costs

Unit costs were attached to the individual resources identified in the RUQ using Unit Costs of Health and Social Care for staff for primary care, and British National Formulary for prescribed medication [20, 21] (Table 1). Data about consultations with health care professionals external to the care home, specific to UI, was categorised according to staff grade and location. Costs for incontinence products and equipment to deliver the intervention (TTNS Neurotrac™ machine, consumables (skin electrodes, wipes, batteries)) were based on market rates for these items. Direct costs included expenditure on absorbent pads and expenditure on other protection products to manage urinary incontinence. Cost of toileting assistance was based on an assumed average of 5 min per resident per visit, and a derived average hourly pay of £36.08 per staff member (based on unit costs for proportions of staff delivering intervention [source: trial data]).

Table 1 Applied unit costs and data sources for unit cost valuation

Intervention costs

Training was delivered by trial staff and an allocated cost was estimated which included time for face-to-face delivery and travel to individual care homes. As training would not be expected to be delivered off site in normal working practice the cost of training facilities was not included. The sunk costs for development of the Handbook and DVD were not included. Care home staff time for training and time to deliver the intervention were costed using staff roles reported for delivery of TTNS/sham intervention. Sources which were used to estimate total cost per participant are given in Table 1.

Data analysis

The total cost per participant was estimated by combining the number of each item of resource used with the unit cost of that item. This provided an estimate of mean cost per participant by treatment group. Differences in mean costs associated with UI products, staff time for toilet assistance and other health care resource use (e.g. GP visits) during routine follow-up were estimated. Independent samples t-test was used to compare resource use by the groups at each time point. Utility change scores were assessed for differences before and after TTNS (6 weeks), at 18 weeks follow up and between groups at each time point.

Missing data

When no data was present for health care NHS contacts, the participant was assumed not to have used the resource category. Data was not imputed for missing DEMQOL or DEMQOL-PROXY responses.

Results

RCT results

The ELECTRIC trial randomised 406 residents with UI from 37 care homes in the United Kingdom (23 Scotland, 14 England). 76% of participants were female, average age 85.5 years (range 58 to 107 years). Trial data indicated that participants (TTNS, n = 197; Sham, n = 209) were similar between arms, that most had severe UI of 400ml per 24 h or more and all wore absorbent pads to manage their UI. The trial primary outcome was volume of urine leaked into pads and the data indicated that TTNS was not superior to sham stimulation in reducing leakage of urine over 24 h.

Quality of life outcomes

No significant difference was found between participants’ HRQoL scores over time, or between treatment and control groups at any time point, for either DEMQOL-U or DEMQOL-PROXY-U (Table 2). Baseline utility scores could be calculated using DEMQOL-U for 35% (n = 141) participants, and using DEMQOL-Proxy-U for 98% (n = 397) participants. Minimum and maximum utility values were reported for both tools at baseline (DEMQOL-U 0.243 to 0.986 and DEMQOL-PROXY-U 0.363 to 0.937). A larger range of mean utility values was observed for DEMQOL-PROXY (0.722 to 0.742) than DEMQOL (0.790 to 0.803) reported by the care home resident. As no evidence of clinical effectiveness was found, and no difference in HRQoL was observed, no further synthesis of costs and benefits to produce incremental cost-effectiveness ratio (ICER) between the two arms was conducted.

Table 2 Participant health-related quality of life measures at baseline, 6-weeks and 18-weeks follow-up, by randomised group

Resource use for continence care

There was very little change in staff time to manage UI, use of assistive devices for visiting the toilet, use of incontinence products to manage UI, primary care appointments related to UI or medication for UI during the study. Table 3 indicates that 85% of participants needed toilet assistance as routine, on average requiring one or two staff members to be involved four or five times in each 24 h. No significant difference was found between TTNS and sham for the value of staff time to assist residents to attend the toilet: £19.17 (SD 13.22) for TTNS and £17.30 (SD 13.33) for sham (per resident in a 24 h period). Similar proportions of special equipment (898 items (433 TTNS, 465 sham)) were used on a daily basis across the groups: mobility aid (~ 40%), transfer aid (~ 25%) and toilet aid (~ 20%). No significant difference was found between groups for use of products related to incontinence management: the average cost was £1.19 (SD £1.51) per participant in 24 h. Low use of primary care health care professionals and very few medications specifically prescribed for UI were reported. 53 participants (21 TTNS; 33 sham) used health care services for their UI. Most contacts were GP surgery appointments (n = 75) or GP care home visits (n = 49), accounting for 79% of all contacts. No significant differences were observed between groups.

Table 3 Resource use summary, by randomised group

Cost of TTNS intervention

The average cost of the training and support package per staff member was estimated to be £121.03 (based on assumption of local trainers (10-mile radius) and excluding economic cost of venue). The cost of delivery of TTNS (exclusive of training) in the trial was estimated to be £81.20 per participant (Table 4).

Table 4 Cost of training activities and TTNS intervention

Cost effectiveness

The trial indicated there was no evidence of clinical effectiveness of TTNS. In the absence of benefit, a claim for cost-effectiveness cannot be made unless there is a reduction in resource use resulting from the new intervention. The use of TTNS did not reduce resources use in terms of staff time or continence pad usage compared to current practice. As the TTNS intervention is in addition to usual care and therefore incurs an additional cost it is not cost effective.

CCA balance sheet

A descriptive comparison of the costs and outcomes (clinical and economic) of the ELECTRIC trial is presented in the cost-consequence balance sheet (Table 5).

Table 5 Descriptive cost consequence analysis balance sheet for the ELECTRIC trial

Discussion

The economic analysis indicated that for the care homes involved in the study there was no meaningful change in resource use associated with continence care over time (pads, toileting assistance, health care use). Although costs were slightly lower for residents receiving TTNS than for the sham group differences were not significant. Changes to usual care pathways for continence care during the trial were the delivery of TTNS/sham intervention and the 24-hour pad collection. The latter being a trial specific activity which would not need to be continued in normal working practice. In line with the main findings of the ELECTRIC trial which reported that TTNS was not found to be clinically effective in this population [22], no evidence of impact on HRQoL (as measured using DEMQOL-U/DEMQOL-Proxy-U) was observed. In addition to the challenges of blinding, poor information about resident’s type of UI and the degree of physical and/or cognitive frailty of participants (see Trial report for discussion of limitations [22]), the developers of the DEMQOL utility index have highlighted that the health state classification system may be limited for individuals with severe dementia [18]. The mean participant Mini Mental State Examination score was 13.1 (SD 9.1) indicating the resident sample had predominantly moderate to severe dementia. A further challenge is that DEMQOL-U and DEMQOL-PROXY-U have been suggested to be more responsive to changes in dementia symptoms than to physical changes [23]. While data about quality of life was successfully collected using both DEMQOL-U and DEMQOL-PROXY-U, completion of DEMQOL by participants was fewer, reflecting the severity of their cognitive impairment. It should also be noted that as the proxy form could be completed by a different person at each of the three data collection timepoints, consistency of response cannot be assumed.

It was notable from the resource data that participants’ dependency on staff to take them to the toilet and the use of transfer and mobility aids were a daily and ongoing requirement. This was reflected in the observed lack of changes in continence care practices and therefore costs of the existing continence care pathways in care homes. If TTNS is effective then residents would be expected to experience a reduced sensation of urinary urgency and increased warning time for the need to void. However, if no additional toilet visits were provided to enable residents to void in a toilet, as opposed to using the absorbent pads to void, any effects produced by TTNS would be unlikely to be recognised. Incontinence in care homes is usually managed using absorbent pads. These can be costly to the care home and health service providers. Usage of continence products to manage UI did not change between timepoints and although costs were slightly lower for residents receiving TTNS than sham, differences were not significant. Only a small number of individuals reported use of primary care health professionals for incontinence related issues. Similarly, a small number of participants were reported as receiving medications prescribed for UI. The absence of anticholinergic medications and the very low reported use of the NHS continence service during the trial period confirmed that the usual continence care approach was to seek to contain UI rather than instigate active treatment for UI, in line with other studies [6, 24].

A cost consequence analysis approach was useful to indicate which costs and outcomes will be most relevant to future continence trials in care homes. Qualitative evidence indicated that a positive impact on laundry (a reduction in items requiring laundering due to UI) had been noted by one care home manager [22]. Data had not been collected about this during the trial and future studies may wish to consider including the collection of such resource data. For the economic analysis, retail prices were used to cost continence products. In practice, lower unit costs per product could be attainable by care homes if they have supplier agreements in place. The main trial results reported no treatment difference between the groups, including for subgroup analysis by falls status [22]. For the economic component of the study a pragmatic decision was made to not collect data on secondary care beyond use of services for continence in order to minimise the amount of data care home staff were required to report. This was based on the view that TTNS was not expected to change any care given to people other than potentially affecting clinical degree of incontinence and thereafter resultant care home continence care pathway practices. However, UI is a known risk factor for falls in care home adults and consequent increased health care costs and so is an important outcome that should be explicitly considered for data collection on a study by study basis. It is the case that staff time is a significant portion of continence-related costs in care homes. The high dependency of residents (physical and cognitive) in general, and high proportion of residents requiring assistance to use a toilet, often compounded by severity of UI, presents practical constraints to continence care in this setting. To impact this in a substantial way is challenging. Research to explore the effects of in-depth training about UI for care home staff, to improve staff knowledge and understanding about causes and types of incontinence, effects of incontinence on residents and different management strategies could provide useful insight.

Implications

Our study adds economic evidence of the costs and consequences of delivering TTNS using electrical stimulation to reduce UI in older care home residents. It suggests TTNS does not impact on current resource use for the management of UI in care homes. However, the trial also found no evidence of clinical effectiveness and no effect on HRQoL of TTNS for older care home residents.

Conclusions

In summary, the evidence from the CCA of the ELECTRIC trial does not suggest that there is an economic case for TTNS in the care home context. The use of TTNS does not change the volume or type of resources used to manage continence in care homes. Residents in both randomised groups continued to receive high levels of staff assistance to use the toilet, use of aids and devices for managing incontinence, including absorbent pads, without significant difference from baseline.