Royal Free London first to recruit patients to kidney dialysis trial

27 July 2023

Patients receiving dialysis at the Royal Free London (RFL) have become the first in the UK to be recruited to a trial looking at what levels of salt in their dialysis fluid is best for the heart.

The four dialysis units at the trust — the Tottenham Hale Kidney and Diabetes Centre, the Mary Rankin Unit at the St Pancras Hospital, Barnet Dialysis Unit and the Edgware Kidney Care Centre — have each been randomly assigned to use one of two levels of sodium for haemodialysis, both of which are within the limits routinely used in the UK. The study at the RFL sites is being led by Professor Andrew Davenport.

All patients receiving treatment at the units are part of the study unless they opt out of data collection.  Researchers will then use the medical records and data routinely collected by the UK Renal Registry and NHS Digital to track the health of these patients. Data collected in the UK as well as China, India, Germany, Malaysia and Canada, where the study is also running, will be used to determine which sodium level is best for the majority of patients. The aim is to recruit approximately 56,000 patients and it is estimated the trial will take four years before results are available.

Sodium levels in dialysis fluid are measured in millimoles per litre (mmol/l). The current range used in routine clinical practice varies widely from 135mmol/l to 141mmol/l. Reducing the level of sodium in the dialysis fluid may improve long term blood pressure and fluid control but can lead to more low pressure or ‘hypotension’ during dialysis. In contrast, a high sodium may not control fluid so well, but should make the dialysis session easier to tolerate.

Units participating in the RESOLVE study will be randomly assigned either 137mmol/l or 140mmol/l for most dialysis sessions.

Professor David Wheeler is the Chief Investigator for the UK study and leads the clinical research team in the RFL’s Centre for Nephrology. Professor Wheeler helped to co-design the study which has been granted £1.6 million by the National Institute for Health and Care Research (NIHR).

He said: “There are approximately 30,000 people on dialysis in the UK. To date we have never done a cluster randomised trial in the dialysis population using an opt out consent model. From the very beginning we are proud to have had patient involvement in the design of this trial. It seems that the majority of dialysis patients are happy for data that we collect routinely for audit purposes to be used for research that may improve patient outcomes.”

Rani Badhan, co-investigator and senior trialist added: “We have worked closely with patients to ensure that historically underrepresented groups such as the elderly and patients from ethnic minority groups could participate in this trial. This is especially important when you consider that both these groups make up a high proportion of dialysis patients. Our patient advisory group have been instrumental in devising the recruitment strategy for the UK and have helped us ensure the study design is acceptable and inclusive to patients from all backgrounds. The patient information and posters were designed by dialysis patients and the study information is available in eight languages so information should be accessible for everyone. One of our patients is also on the UK steering committee for the trial.”

David added: “This trial asks one of the big-ticket questions that experts in this field have been asking for years and it is fantastic that we, as one of the first ever dialysis centres to treat patients in the UK back in 1961, are now leading on the RESOLVE study. Large studies of this nature require worldwide co-operation to achieve the necessary number of patients to answer these kinds of clinical questions.”

The study is funded by the NIHR Health Technology Assessment (HTA) Programme and sponsored internationally by the University of Sydney. In the UK, the trial is being coordinated by the Comprehensive Clinical Trials Unit at UCL. The RFL is a leading site and collaborator on the grant.

As soon as the researchers determine which sodium level is better for the heart, all patients will switch to that level - unless it is proven there is no difference between the two. 

A summary of the results of the research will be available in the RFL’s dialysis units when the project is complete.

Pictured: Professor David Wheeler and Rani Badhan