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Renal Risk in Derby (RRID) Study


For Participants

We are grateful to the many people who volunteered to participate in this study. Your contribution has been very valuable in helping us learn more about chronic kidney disease (CKD) so that each person with CKD can be offered the best treatment for them as an individual. As summarised below, this means that most people with CKD do no need further tests or referral to a Kidney Consultant. We have already learned a great deal and our results have been published in several journals (see bibliography section).

The most important finding so far are:

  1. The majority of people with CKD cared for by family doctors have only mildly reduced kidney function which is unlikely to cause any symptoms.
  2. Only a small proportion of people (6%) with CKD that is diagnosed by their family doctors require referral to a kidney consultant for further tests. The majority can be effectively cared for by their family doctor and simply require an annual check of their kidney function.
  3. CKD is often associated with other medical conditions and this should be taken into account when deciding on the best treatment.
  4. High blood pressure is commonly associated with CKD and it is important to treat this adequately.
  5. High salt intake is associated with factors that suggest a poorer outcome in people with CKD.
  6. Reducing salt intake is associated with better control of blood pressure in people with CKD.
  7. Vitamin D deficiency is present in a small proportion of people with CKD (6%) and there may be some benefit in checking for this because it is easy to treat.
  8. Skin autofluorescence and arterial  stiffness measurements may be useful and simple ways to identify people with CKD who are at higher risk for worsening of their kidney and/or heart disease  but more research is required to confirm this.
  9. The majority of people with CKD in our study had stable kidney function over 5 years (34%) and in a small but significant proportion (19%) the kidney function improved over time such that they no longer fulfilled the criteria for a diagnosis on “CKD”. Only a very small minority (0.2%) required dialysis by the end of 5 years.


We plan to follow people who participated in this study again at 10 years after the first study visit. This will probably involve a simple blood test and completion of a questionnaire. The exact format will be decided closer to the time. The RRID study has joined the International Network of CKD Cohort Studies (iNET-CKD) which is sponsored by the International Society of Nephrology and aims to improve knowledge and understanding of CKD worldwide on their website: http://www.theisn.org/initiatives/inet-ckd

Involvement of NHS Digital in Data Collection

The Renal Risk in Derby (RRID) study uses an organisation called NHS Digital to obtain some of the information needed for the research. NHS Digital has replaced the NHS Information Centre, which was mentioned in previous study documentation.  As explained in the Participant Information Sheet, we provided NHS Digital with some participant details including full name, date of birth, NHS number and address. The data was sent using encryption and NHS Digital has robust measures in place to ensure that confidentiality is maintained. This personal information will not be shared with any other organisation. 

To facilitate the study NHS Digital supplies the Chief Investigator, Prof Maarten Taal, with the following information:

  1. The date and cause of death of any participant who dies during the follow-up period of 10 years. This information is obtained from the Office of National Statistics and is derived from death certificates.
  2. The date and reasons for any hospital admissions during the follow-up period. This is obtained from Hospital Episode Statistics and is comprised of data routinely supplied to NHS Digital by all hospitals in the NHS.


Participants are identified by name in the initial data that is received from NHS Digital. This is stored on a secure server in the Royal Derby Hospital and only a small number of people who are involved in the study have access to it. Before any analysis is performed, the information is anonymised by replacing the participant name with a study number. The key that links participant names to the study numbers is stored on a secure computer server at the Royal Derby Hospital and this can be accessed only by Professor Taal and research staff involved in the study.

Participants are free to withdraw from the study at any time, without giving a reason. This will not affect the standard of care they receive. In general, we would prefer to continue to use any data collected about a participant prior to the time of withdrawal and will ask any participant who withdraws for their permission to do this.