This site is optimised for modern browsers. For the best experience, please use Google Chrome, Mozilla Firefox, or Microsoft Edge.


This is a new site which is still under development. We welcome your feedback, which will help improve it.

Feedback form

Case study: Registry-facilitated trial investigates delivery of vitamin D for dialysis patients

The NIHR research infrastructure supports the delivery of complex and innovative clinical trials.

Find out more

A registry facilitated trial

Clinical Need

Approximately one in seven people will develop a rare disease at some point in their lives.  Of those affected, around 75% are children, and 30% of rare disease patients die before their fifth birthday. The number of different rare conditions is currently estimated to be between 5,000 and 8,000.*

Renal medicine deals with the kidneys which can be affected by a large number of rare diseases, often causing chronic or end stage kidney disease. Most rare diseases are genetic with no known cure, as a result there is an urgent need for more research. But finding and recruiting patients with rare kidney disease can be challenging, or was, until RaDaR came along. This important research registry is currently recruiting children and adults with 58 different rare renal conditions, and the number of conditions continues to grow, says RaDaR Project Lead, Dr Danny Gale:

“RaDaR commenced 10 years ago as an  initiative designed to collect information about patients with rare kidney disease to facilitate research, and share the expertise and learning from that research.  It has a dedicated website ( and pulls together information from patients with 58 different conditions which we have organised into 30 rare kidney disease groups. But these numbers are constantly expanding. New disorders continue to be added, for example, inherited kidney cancer is a new condition that we are now recruiting for.”

As well as being the Project Lead, Dr Danny Gale is Associate Professor of Nephrology at University College London and Chair of the Rare Disease Committee for the Renal Association - the UK’s professional organisation of nephrologists and renal scientists. He explains how RaDaR works:

What is RaDaR?

“RaDaR was set up with funding from Kidney Care UK and  Kidney Research UK and is supported and coordinated  by the Renal Association. Currently we have 101 NHS sites contributing to RaDaR, which includes all UK paediatric renal units and the majority of adult renal centres. To date, 23,814 patients have been recruited. (As of 2 September 2019).

“The data is housed and managed using the same informatics infrastructure as the UK Renal Registry which was set up in 1995 to collect clinical and outcome data from recipients of dialysis and kidney transplants to help standardize and improve care. RaDaR focuses specifically on rare renal conditions and holds detailed information on who has these conditions, where they are in the country, what treatment they are receiving and how they are responding to treatment.

“All 23,814 patients recruited have provided consent for their routinely collected clinical data to be fed into RaDaR, this includes all their eGFR (kidney function monitoring) test results. We can access all their information whether they were diagnosed one year ago or 50 years ago, making it a valuable resource for retrospective research. Plus, it is a fully automated system and the data is refreshed regularly, which enables both prospective and real-world research.

“The majority of patients have also given consent to be contacted about interventional research opportunities and, although the data is anonymised for observational research, patient details are recallable. A message is sent to the patient’s clinician at site level who can re-identify the patient and invite them to take part in a study. This means that investigators can conduct virtual screening via RaDaR. It is a very efficient way to rapidly access patients with rare kidney disease - a great facilitator of interventional studies.”

“We also have a patient portal on the RaDaR website where patients can login and see their test results. Soon we will be adding a list of actively recruiting interventional rare disease studies and sites to the RaDaR website so that patients can see if a trial is happening near them, allowing them to initiate contact if they wish to learn more about it.”

How RaDaR supports academic and commercial research

Access to RaDaR data is granted through the relevant Rare Disease Group which, Dr Gale says, are interested in hearing from any clinicians who may like to use RaDaR as part of a research study or clinical trial:

“RaDaR has supported a number of studies to date. It was used to identify patients to recruit to NURTuRE and also for two renal studies that are part of the NIHR Bridge Project. The latter is particularly interesting because it included large-scale Whole Genome Sequencing to help us to identify genetic biomarkers - or even the cause of disease in some patients.  A number of studies have been published from the Bridge Project and the paper reporting the key findings from one of the renal conditions is currently under review by an international journal.

“These are both academic studies and academic researchers access the anonymised data by approaching the relevant Rare Disease Group. There are, of course, protections on how the data is exported and used, for instance it cannot be passed onto other researchers. For life sciences companies there is a slightly different process; they ask a specific research question and pay a fee. They do not receive the raw data, instead our analysts do the work and the company is provided with the answer to their question.

“It is an efficient way to conduct virtual screening for a study or trial. It would take huge efforts and resources to find and recruit these patients on a study by study basis simply because of the rarity of the conditions.  But we have vast numbers already recruited. For example, we have data from almost 6500 patients with autosomal dominant and around 200 with autosomal recessive polycystic kidney disease, which are genetic disorders.”

“We’ve had interest from several companies and we have already helped some that are planning multinational interventional studies. We’ve provided advice on trial design, helped set eligibility criteria, estimated recruitment levels, and suggested which sites to place studies at.”

How the NIHR Clinical Research Network has supported RaDaR

RaDaR was added to the NIHR Clinical Research Network Portfolio in 2010 with a recruitment target of 25,000 patients by March 2020. With 23,814 already recruited, and 252 new recruits in August (2019) alone, the target is firmly in sight. Dr Gale explains how important this support has been:

“RaDaR would not have been anywhere near as successful as it has, without support from the NIHR Clinical Research Network. This is a large study which requires nationwide coverage and the NIHR Clinical Research Network, which covers the whole of England, was pivotal in activating the study at site level. Getting all those 101 sites set up and recruiting took a huge amount of energy and support.

“The official end date on the NIHR Clinical Research Network Portfolio is March 2020 but the reality is that we will continue to recruit to RaDaR. We don’t really have a numerical target as such. Our experience has been that patients are frequently keen to participate, and keen that we use their data for research. Our aim is for joining RaDaR to continue to be an option for all rare renal disease patients, wherever they are in the country.”

Making the UK an attractive destination for clinical research

When asked to summarise what RaDaR means for the UK, Dr Gale was quick to convey how RaDaR sets the UK apart from other countries:

“RaDaR makes the UK an attractive place to establish international rare renal trials and studies. Registries do exist in other countries but I am not aware of any that are as broad (in terms of numbers of rare diseases they include) or that provide the same granularity or volume of hospital laboratory data as RaDaR.

“The sheer volume of patients really is one of RaDaR’s key selling points - along with the age range of patients, the fact that it is automatically fed with real-time eGFR results (kidney function data), plus its nationwide reach. It’s an incredibly rich data source. Through RaDaR we can see data across decades and learn how kidney function, for instance, changes over time. RaDaR does not just provide a snapshot, it provides a long-term view. It’s a very powerful way of viewing disease progression. But more importantly, it brings hope of finding new treatments for rare renal diseases faster.”

More about registry facilitated trials

A research registry is a database of clinical data from patients with a particular disease or condition. When a patient consents to become part of a research registry they are normally:

  • allowing all or some of their electronic health record to be anonymised and added to a database;
  • and giving permission for that data to be accessed by investigators for observational research purposes.

Research registries offer enormous opportunities for clinical research and present a very efficient way of conducting studies.  The primary benefit is that investigators do not need to recruit their own cohort of patients, in effect, the recruitment is already done. Registries often provide access to historical data which spans many years, which enables retrospective longitudinal studies. Some registries also have a mechanism for ongoing collection of data, meaning the database is updated, and can therefore be used to conduct prospective studies.

For the patient there are also advantages. The burden of participating in multiple studies simultaneously is low.  In addition, during the recruitment process, the patient may give their consent to be contacted about interventional research. In such cases the registry can be used for rapidly identifying and pre-screening potential participants giving those patients opportunities to access new treatments that are not yet widely available.

RaDaR (National Registry of Rare Kidney Diseases) is one such registry which offers all of the above and currently holds data from almost 24,000 patients with rare kidney disease.