Plain English Summary
Background and study aims
Most patients who develop kidney failure choose unit-based haemodialysis treatment. One of the main functions of dialysis is to control the amount of fluid in the body. Too much fluid can lead to persistently raised blood pressure that damages he heart and increases the risk of stroke, and may cause fluid to collect in the lungs leading to breathing difficulties which if allowed to get out of control could result in death. Too little fluid causes dehydration, cramps and low blood pressure on dialysis and more rapid or complete loss of any remaining kidney function along with its associated benefits. Bioimpedance is a simple, bedside measurement giving information about body composition, in particular how much excess fluid is present. Clinicians can use this to guide how much fluid should be removed from the body in conjunction with the normal clinical assessment of the amount of fluid in the body, but it is not known if this results in better decisions and outcomes for patients. The bioimpedance information can be shared with patients to help them understand the objectives of their treatment, potentially improving confidence in how their dialysis care is managed. The research is to test whether taking regular measurements with a bioimpedance device improves outcomes for people who have recently started haemodialysis treatment for kidney failure. In particular, the study aims to see if this helps patients maintain their remaining kidney function, as this is associated with improved survival, fewer symptoms of kidney failure, fewer side effects of dialysis treatment and a better quality of life including confidence in managing their health, and cost benefit analysis.
Who can participate?
Adults (aged at least 18) starting kidney dialysis due to advanced kidney disease.
What does the study involve?
Participants are randomly allocated to one of two groups. Those in group 1 are regularly assessed with a bioimpedance device as well as receiving standard treatment. Those in group 2 receive standard treatment only. All participants are assessed at the start of the study, then once a month for three months. Assessments then continue every other month for up to the next 20 months. These assessments compare between the two treatments how quickly kidney function is declining, the side effects of treatment, symptoms of kidney failure, blood pressure and heart function, how confident the patient feels regarding managing their own health and the costs involved.
What are the possible benefits and risks of participating?
Not provided at time of registration
Where is the study run from?
Keele University Clinical Trials Unit (UK)
When is the study starting and how long is it expected to run for?
June 2016 to January 2021
Who is funding the study?
National Institute for Health Research (UK)
Who is the main contact?
Prof. Simon Davies
Prof Simon Davies
Royal Stoke University Hospital
University Hospital of North Midlands NHS Trust
+44 (0)1782 676346
Protocol V3, 15/12/2017
Bio-Impedance Spectroscopy To maintain Renal Output: a randomised controlled trial
The aim of the research is to determine if incorporation of bioimpedance into the setting of the post dialytic weight reduces loss of residual kidney function in incident centre-based HD patients, with the potential to improve clinical outcomes, in particular dialysis related symptoms, hospitalisation and survival.
North of Scotland REC 2, 12/09/2016, ref: 16/NS/0094
Pragmatic multi-centre open-label prospective randomised controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Urological and Genital Diseases
Patients starting haemodialysis as an outpatient who still have some remaining kidney function will be invited to participate in a clinical trial that compares current best practice with the same but additionally guided by regular bioimpedance measurements. The trial will randomly assign, 516 patients from 30 dialysis units across the UK. The random allocation will be 1:1 to the Bioimpedance intervention and control groups, stratified by centre (main or satellite centre, where dialysis will commence) and planned versus unplanned start.
Primary outcome measure
Time to anuria ( loss of urine output), <100ml/day or 200ml in the short inter-dialytic period confirmed by a further collection after 2 weeks to exclude temporary illness.
To measure the primary outcome urine volume and residual renal clearances to be measured at baseline, monthly for 3 months and alternate months (for up to a further 20 months) until trial completion, or the primary endpoint is reached.
Secondary outcome measures
Determining the effect of the use of bioimpedance in assessing the amount of fluid in the body to guide the setting of the post-dialytic target weight on:
1. The rate that kidney function reduces ( baseline, monthly for 3 months, then alternate months for up to 20 months)
2. Vascular access failure, cardiovascular events, hospital admissions, death and including the use of routinely collected data from the UK Renal Registry, Hospital episode Statistics and the Office for National Statistics (and equivalent bodies in Wales, Scotland and Northern Ireland) via the UK Renal Registry. These are measured at baseline, and at the end of the study, routine clinical data collected by dialysis units for the UK Renal Registry returns will be made available for this study. Death will be recorded in real time during the study
3. Measures of dialysis efficacy and safety (body fluid assessment, blood pressure). These are measured at baseline, monthly for 3 months, then every 3 months for up to a further 20 months
4. Patient reported outcomes including quality of life, dialysis symptoms, functional status. These are measured at baseline, then 3 monthly for up to 24 months
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Adults aged >18 years commencing centre-based maintenance haemodialysis due to advanced kidney disease CKD stage 5, planned or unplanned, via arterio-venous fistula, graft or central venous catheter (i.e. with or without permanent vascular access)
2. Commencing dialysis on any regimen, including having incremental dialysis initiation
3. Residual kidney function: For patients who have not yet started dialysis treatment they should have a daily urine volume > 500ml/day and/or a or a measured mean urea and creatinine clearance >3ml/min/1.72m2 determined from a 24 hour collection; for patients already on dialysis they should have a urine volume >500ml during the short inter-dialytic period and/or a measured mean urea and creatinine clearance >3ml/min/1.72m2, determined from the same timed inter-dialytic urine collections and an average of the post- and pre-dialysis plasma urea and creatinine concentrations.
Target number of participants
516 patients will be included in total
Participant exclusion criteria
1. Unable or unwilling to give informed consent
2. Unable to comply with trial procedures, e.g. collection of urine output
3. Likely survival prognosis or planned modality transfer < 6 months
4. Subjects with limb amputations when the foot is not accessible AND it is not possible to take hand to hand measurements
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Keele University Clinical Trials Unit Arthritis Research UK Primary Care Centre Research Institute for Primary Care Sciences
Directorate of Engagement and Partnerships
IC2 Keele University Science and Innovation Park
+44 (0)1782 733374
National Institute for Health Research
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
The following outputs are planned:
1. Publication of the trial protocol (in an open access journal to coincide with the start of the trial).
2. Efficacy of the intervention, to include primary and selected secondary endpoints, especially dialysis related efficacy, safety and significant events.
3. Economic evaluation of the intervention and analysis of the benefits of residual kidney function.
4. In-depth analysis of effect of the intervention on the patient activation and engagement with fluid management
5. The impact of dialysis unit practice patterns on primary and secondary endpoints.
6. Publication of the clinically validated fluid assessment tool and associated educational material, with the potential develop this into an application suitable for hand-held devices
The dissemination plan will be developed in close collaboration with the study oversight committee (Advisory and Dissemination Board facilitated by Kidney Research UK on behalf of the UK Kidney Research Consortium) and the steering group. Routes of dissemination will be as follows:
National Meetings (to include study updates and findings):
Renal Association and British Renal Society (e.g. annual Kidney Week, usually multidisciplinary meeting covering all aspects of nephrology and dialysis treatment).
International Meetings (via submitted abstracts):
American Society of Nephrology, European Dialysis and Transplantation Association/European Renal Association, European Dialysis and Transplantation Nurses Association, International Society of Nephrology.
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
2017 protocol in: https://www.ncbi.nlm.nih.gov/pubmed/28441936