Randomised controlled trial of dialysate cooling for preservation of cognitive function in haemodialysis
| ISRCTN | ISRCTN67955356 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN67955356 |
| Integrated Research Application System (IRAS) | 345755 |
| Central Portfolio Management System (CPMS) | 63214 |
| National Institute for Health and Care Research (NIHR) | 208855 |
| Sponsor | University Hospitals of Derby and Burton NHS Foundation Trust |
| Funder | National Institute for Health and Care Research |
- Submission date
- 23/04/2026
- Registration date
- 07/05/2026
- Last edited
- 07/05/2026
- Recruitment status
- Recruiting
- Overall study status
- Ongoing
- Condition category
- Mental and Behavioural Disorders
Plain English summary of protocol
Background and study aims
Thinking and memory problems affect working memory and people's abilities to remember and perform daily life tasks. Thinking and memory problems are common in people receiving haemodialysis. Haemodialysis can affect blood pressure and the brain blood supply, which may lead to worsening in thinking and memory abilities. There are currently no treatments to protect against thinking and memory problems in people receiving haemodialysis. Dialysate cooling is a method of reducing the temperature of the fluid used in the haemodialysis machine and has been shown to have positive effects on blood pressure in other studies. This study will explore whether dropping the temperature of dialysis fluid by 0.5 degrees (dialysate cooling) can preserve thinking and memory functions in people receiving haemodialysis.
Who can participate?
Patients over the age of 18 years who are receiving haemodialysis
What does the study involve?
The study involves participants undergoing their usual haemodialysis. Some participants will be randomly allocated to have dialysis at a cooler temperature (0.5 degrees lower than body temperature). At baseline and after 1 year, all participants will complete a number of questionnaires and cognitive assessments
What are the possible benefits and risks of participating?
Dialysate cooling is safe and no riskier than usual dialysis treatment. Some patients do report coldness or feeling cold during dialysis treatment.
This study will help us answer the question of whether dropping the temperature of the dialysis fluid by 0.5 degrees below the person's body temperature is the way to preserve thinking and memory functions in people receiving haemodialysis.
Where is the study run from?
Derby Clinical Trials Support Unit (UK)
When is the study starting and how long is it expected to run for?
April 2026 to October 2027
Who is funding the study?
National Institute for Health and Care Research (NIHR) (UK)
Who is the main contact?
Derby Clinical Trials Unit, uhdb.coolhdstudy@nhs.net
Contact information
Scientific
422 Medical School, Derby Clinical Trials Support Unit, Royal Derby Hospital
Derby
DE22 3DT
United Kingdom
| Phone | +44 (0)7472910392 |
|---|---|
| daniel.davis6@nhs.net |
Principal investigator
School of Medicine, Royal Derby Hospital
Derby
DE22 3DT
United Kingdom
 ORCID ID |
0000-0003-1681-9048 |
|---|---|
| Phone | +44 (0)7867533453 |
| tarek.eldehni@nhs.net |
Public, Scientific
422 Medical School, Royal Derby Hospital
Derby
DE2 23DT
United Kingdom
| Phone | +44 (0)1332340131 |
|---|---|
| uhdb.coolhdstudy@nhs.net |
Study information
| Primary study design | Interventional |
|---|---|
| Study design | Randomized controlled trial |
| Secondary study design | Randomised controlled trial |
| Scientific title | Randomised controlled trial of dialysate cooling for the preservation of cognitive function in haemodialysis patients (COOL HD) |
| Study acronym | COOL HD |
| Study objectives | This study aims to answer the question of whether lowering the dialysis fluid temperature by 0.5 degrees below the person's body temperature leads to preservation of thinking and memory functions in people receiving Haemodialysis. The study will measure secondary outcomes such quality of life, hospitalisation episodes and length of these hospital admissions, the degree of frailty and any adverse events related to cooling such as feeling cold and heart and stroke events. |
| Ethics approval(s) |
Approved 19/02/2026, Yorkshire & The Humber - Leeds East Research Ethics Committee (N/A, N/A, N/A, United Kingdom; N/A; leedseast.rec@hra.nhs.uk), ref: 26/YH/0023 |
| Health condition(s) or problem(s) studied | Cognitive function in haemodialysis patients |
| Intervention | This is a randomised study, meaning participants are assigned by chance to one of two groups for 1 year: 1. Dialysis fluid is set at 37°C (normal body temperature) 2. Dialysis fluid is set at 0.5°C below the person’s body temperature. Participants will have two main study visits at the start of the study and 1 year later At both visits, trained researchers will assess: 1. Thinking and memory (using simple tests) 2. Frailty (how physically vulnerable someone is) 3. Quality of life (how people feel day-to-day) These assessments will be done before a dialysis session. At the start, researchers will also record: 1. Age, sex, ethnicity 2. Height, weight, blood pressure 3. Dialysis details and medical history 4. Current medications 5. Routine blood test results (already taken as part of normal care) During the year dialysis temperature will be checked monthly; blood results, hospital admissions, and heart-related events will be reviewed every 3 months. Safety will be monitored throughout the study. |
| Intervention type | Other |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) |
1. Other cognitive domains: processing speed, inhibition, attention, perception and general cognition and memory measured using Digit symbol matching task, Flanker Test and Letter Number Sequence Task at baseline and 12 months |
| Completion date | 31/10/2027 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Mixed |
| Lower age limit | 18 Years |
| Upper age limit | 100 Years |
| Sex | All |
| Target sample size at registration | 356 |
| Key inclusion criteria | 1. The participant is receiving maintenance in-centre haemodialysis 2. Over 18 years of age at time of consent 3. The participant is able and willing to provide written informed consent |
| Key exclusion criteria | 1. Participants with confirmed diagnosis of dementia 2. Participants who lack capacity to consent 3. Participants having dialysis less than three times a week 4. Pregnant participants |
| Date of first enrolment | 01/04/2026 |
| Date of final enrolment | 01/10/2026 |
Locations
Countries of recruitment
- United Kingdom
- England
Study participating centres
Uttoxeter Road
Derby
DE22 3NE
England
Queens Medical Centre
Derby Road
Nottingham
NG7 2UH
England
Infirmary Square
Leicester
LE1 5WW
England
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|
Editorial Notes
23/04/2026: Study's existence confirmed by the NIHR.
