How does starting haemodialysis affect brain, bladder and eye health?
Research type
Research Study
Full title
How does starting haemodialysis affect brain, bladder and eye health?
IRAS ID
227132
Contact name
Catherine Pennington
Contact email
Sponsor organisation
North Bristol Trust
Duration of Study in the UK
0 years, 11 months, 30 days
Research summary
Research Summary
There is growing interest in how starting haemodialysis for kidney failure affects different parts of the body, including the brain, eyes and bladder. Haemodialysis (also called ’dialsysis’) is a process for purifying the blood when a person’s kidneys have stopped working. This is an increasingly important area as the population ages, and an increasing number of older adults with kidney failure have to decide whether or not they want to start haemodialysis. \nHaemodialysis causes major changes to body physiology, with alterations in fluid levels and the level of blood waste products and toxins. There are concerns that these changes could impact on brain, bladder and eye health. Memory and thinking could be improved by better control of waste products, or could be worsened by fluid shifts in the brain. The fluid shifts could also worsen eye conditions, and affect urine production. \nIn this study we will recruit 2 groups of people who have end stage kidney failure who are planning to start haemodialysis. 1 group will have eye assessments approximately a month before, and a month after starting haemodialysis. The other group will have tests of memory and thinking before and after starting haemodialysis. Both groups will also complete questionnaires about general well-being, and about bladder symptoms in particular. \nPeople receiving haemodialysis already have to attend frequent hospital appointments, and by recruiting 2 separate groups (rather than 1 group undergoing both eye and memory tests), we will reduce the time burden on participants, and make the study more accessible.
Summary of Results
This feasibilty project was undertaken between March 2017 and October 2019 to explore the impact of starting haemodialysis (HD) on brain, bladder and eye functioning. Both chronic kidney failure and HD cause major physiological changes. A single session of HD results in large, acute, haemodynamic and metabolic changes. This may theoretically compromise cognitive function, contribute to diabetic macular oedema, and impact on urinary frequency and nocturia. Conversely, better control of uraemic toxins and metabolic status could improve cognition. We aimed to recruit people with end-stage renal failure about to start HD, with assessment before and after starting regular HD. Due to the high burden of hospital appointments in these patients two separate groups were planned – the first group having cognitive testing at North Bristol Trust (NBT), and the second tests of visual functioning at University Hospitals Bristol (UHB). The project was led by Dr Pennington, Consultant in Dementia Neurology, NBT & honorary Clinical Lecturer, University of Bristol (UoB), in conjunction with Prof. Pat Kehoe, UoB, Prof. Julian Hughes, RICE Professor of Old Age Psychiatry, UoB, Prof Marcus Drake, UoB, Dr Denize Atan, Consultant Senior Lecturer in Ophthalmology, UoB, Dr Philip Clatworthy, Consultant Neurologist (NBT) & Senior Clinical Lecturer in Stroke, UoB and Dr Albert Power, Consultant Nephrologist, NBT. Additional support was provided by Dr Caskey, Consultant in Renal Medicine and the renal medicine team. The South West Exeter NHS Research Ethics Committee (REC reference 17/SW/0133) gave ethical approval.
Recruitment
An experienced research assistant, working in close communication with renal nurses and consultants, carried out recruitment. Potentially eligible patients were identified by the renal team at Southmead Hospital and contact details were passed on to a research assistant for further contact about the study. Patients were sent an information sheet via post and followed-up by telephone to confirm trial participation. Six patients were contacted about participation by a research assistant of whom 1 was lost to follow-up due to unsuccessful contact following postage of trial information, 3 declined (1 following further information about the study and 2 decided they felt too unwell to participate) and 2 needed to withdraw due to initiation of dialysis prior to study visit.
A number of issues were identified which adversely affected recruitment. Patients starting dialysis typically did so at very short notice, often in response to a deterioration in their overall clinical condition. This left only a very short time window for patient identification, contact, and assessment at a point when individuals were clinically unwell and already attending multiple hospital appointments. We had anticipated that patients would potentially have a number of hospital appointments already, and planned to have flexibility in place of assessment, plus splitting study groups and offering participants a choice of hospital location. However we did not anticipate that HD decision making would be very fast-paced, with individuals often starting HD less than 2 weeks after the clinical decision to start HD was made. We amended the study timelines (with appropriate ethical approval) to allow greater flexibility in assessment timing, but were still unable to recruit to this feasibility study.
The primary limiting factor for recruitment was insufficient numbers of patients starting dialysis in a planned way. There had been recent changes in dialysis capacity, with dialysis shifts being closed on satellite units around the Bristol catchment area due to low nursing staff numbers. This put further pressure on the main NBT renal unit (where all patients start dialysis, prior to moving to a satellite unit closer to their home). We also lacked an early career fellow or research nurse within the renal unit who could have facilitated recruitment. Whilst the RA working on this project was an excellent member of staff, they were not physically located in the renal unit and this impacted on lines of communication and speed of potential participant referral.
Conclusions
Identifying patients who will be starting HD within a pre-specified future time-frame is very challenging, largely due to the rapid nature of clinical decision making. These people also face a high burden of hospital appointments and may physically be experiencing a range of adverse symptoms, including fatigue. Any study seeking to recruit from this population would benefit from having a flexible time window for pre-HD assessments, and potentially assessing a wide pool of people with end-stage renal failure, in anticipation of some (but not all) participants commencing HD. Ensuring key research team members are embedded with the renal team would also enhance referrals of possible participants, and speed up the recruitment process. Offering home visits for assessments where possible may also reduce barriers to research participation.REC name
South West - Cornwall & Plymouth Research Ethics Committee
REC reference
17/SW/0133
Date of REC Opinion
31 Aug 2017
REC opinion
Further Information Favourable Opinion