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Management of chronic kidney disease in primary care

Nicola Thomas
RGN BSc (Hons) MA
Senior Lecturer in Renal Care, City University London
Chair of CKD Forum, British Renal Society

This article will review the recommendations from the recent publication of the NICE guidance on early identification and management of adults with chronic kidney disease (CKD), and will discuss how to manage people with CKD with
reference to the Quality and Outcomes Framework.

The past five years have seen significant changes in the management of people with kidney disease in primary care. These changes have been of great benefit to people with the condition and have resulted in those at risk being identified much sooner than before.

As a result, strategies to slow down the progression of the condition can be started much earlier. However, this has meant that nurses working in primary care have had to learn about and adapt their practice to the recent recommendations, which for many has meant an increased workload.

Changing the way we think about kidney disease
There have been a number of important national initiatives concerning the care of people with chronic kidney disease (CKD) in recent years, including:

  • The recommendation that all hospital laboratories should report estimated glomerular filtration rate (eGFR) as a measure of kidney function from April 2006.
  • A new Quality and Outcomes Framework (QOF) domain for CKD in 2006 (with amendments to the domain in 2008 and 2009).
  • The publication of National Institute for Health and Clinical Excellence (NICE) guidance for CKD in September 2008.1
  • Collectively, these initiatives have had an enormous impact on the way in which people with CKD should be cared for.

Quality and Outcomes Framework for chronic kidney disease
Table 1 shows the indicators related to CKD in the QOF of the General Medical Services contract. In summary, the management of people with CKD (according to the QOF) includes making a register of people with the condition, recording their blood pressure and managing to a target of Each of these actions will now be discussed in more detail below.

[[Tab 1 CKD]]

Producing a register of people with CKD
Measurement of kidney function
Traditionally, kidney function has been measured by serum creatinine alone. The value of serum creatinine is determined by the rate of production of creatinine, which is dependent on muscle mass, as well as the excretion rate. Because of wide variation in patients' body size, weight and muscle mass, serum creatinine is an inaccurate measure of kidney function, and a normal serum creatinine result does not necessarily mean that the patient has normal kidney function.

It is now recommended that kidney function should be assessed by a much more accurate measure, the estimated glomerular filtration rate (eGFR). This allows people with early CKD to be recognised much earlier, and enables early intervention to prevent progression of deteriorating kidney function.

A formula is used to estimate GFR, which is why the result is called an estimated GFR. The formula requires the gender, age, serum creatinine and ethnicity of the patient. Almost all hospital laboratories in the UK now report eGFR alongside serum creatinine. This means that blood samples sent for serum creatinine will be returned with a value for eGFR as well as for creatinine. If a person is of African or Caribbean ethnicity (not mixed race), the eGFR value needs to be multiplied by 1.21 by the person reviewing the result, unless the hospital laboratory has already made the correction. 

Staging of CKD
The staging of CKD is now internationally recognised and is based on the Kidney Disease Outcome Quality Initiative (KDOQI) study.2 However, the staging of CKD has been amended in the recent NICE guidance with the inclusion of two categories for stage 3 CKD, namely stages 3a and 3b. The amended staging, as recommended by NICE in 2008, is shown in Table 2.

[[Tab 2 CKD]]

Placing people on the register
CKD is defined as either kidney damage (proteinuria, haematuria or anatomical abnormality) or eGFR

Age-related decline in GFR can be common, and a loss of up to 1 ml/min/1.73m2 for every year beyond the age of 40 is frequently quoted. Thus, the average expected GFR of a healthy 80-year-old can be as low as 60 ml/min/1.73m2. This decline is probably a result of vascular disease rather than a "normal" finding, and should still be treated with cardiovascular risk factor intervention. Use of the formula to estimate GFR can identify a high proportion of older women as having CKD, and an appreciation of an individual's age is therefore essential in interpretation.

It may be an appropriate decision for a small minority of people not to be placed on the register, especially if the eGFR is borderline stage 3, but this must be assessed on an individual level. It is important to note that in people over 70 years, an eGFR in the range 45-59, if stable over time and without any other evidence of kidney damage, is unlikely to be associated with CKD-related complications.

People on the register should be informed as such, although the words used to explain this to people need to be chosen carefully. For example, it may be helpful to use the terms "kidney damage" or "reduced kidney function" (rather than CKD) and explain that kidney damage can be part of the normal ageing process.

Prevalence of CKD
It is not clear how many people in the UK have CKD stages 3-5, as data have not been routinely collected until recently. Recent QOF data (see http://www.ic.nhs.uk/qof) have shown an overall recorded prevalence of 4.1%. These data show that over 4% of adults in England are now recognised to have CKD and are on primary care CKD registers. However, compared with some studies,3 it may mean that around 50% of people with stage 3-5 kidney disease have not yet been identified.

The variance between practices in every primary care trust (PCT) remains high, so there is much work to do to ensure that people with this condition are identified and as a result, receive optimal care.

Blood pressure control
It can be difficult to control blood pressure in people with CKD. It is important to recognise that the QOF target (

The treatment for people with diabetes is to control blood pressure with either an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin receptor blocker (ARB). In people without diabetes the advice is more complex and is as follows:

  • Hypertension and ACR
  • Hypertension and ACR >30 mg/mmol: offer ACEIs/ARBs.
  • ACR ≥70 mg/mmol with or without hypertension: offer ACEIs/ARBs.

Generally, the advice is to treat with ACEIs first, then move to ARBs if ACEIs are not tolerated. People with CKD should be encouraged to report side-effects, such as a tickly cough with an ACEI, as an alternative can be easily found.

Proteinuria
It is now recommended that everyone with CKD should have their urine tested for protein. NICE (2008) has recommended that an albumin-creatinine ratio (ACR) should be used to quantify urinary protein, not a dipstick or protein-creatinine ratio (PCR). This has brought into line the way in which urinary protein is measured for both the diabetic and non-diabetic population. In other words, ACR is now the recommended method for detecting and identifying proteinuria for everyone with CKD as it has greater sensitivity than PCR for low levels of proteinuria.

An ACR should be taken in a plain pot with no preservative, in a specimen that is reasonably concentrated. A urine sample taken in the early morning is recommended but not essential.

Urine testing rates can be increased if urine samples are taken immediately following a consultation rather than giving people a urine pot to return with a sample at a later date. However if ACR >30 mg/mmol and

For people with diabetes an ACR >2.5 mg/mmol in a male or >3.5 mg/mmol in a female identifies microalbuminuria. The action for those with diabetes with an abnormal ACR is to offer ACEIs or ARBs, even if blood pressure is below 130/80 mmHg.
An important message is that the presence of protein in the urine is an independent risk factor for cardiovascular disease.4
Statins can be used for the primary prevention of cardiovascular disease in the same way as in people without CKD.

Education and self-management
It is important that people with CKD are given good information and support for their condition (see Resources for patients and professionals at the end of this article). Key messages (see Table 3) can be delivered alongside information leaflets and other resources such as DVDs. It can be helpful to encourage them to ask questions such as:

  • What is my kidney function? Is it stable?
  • What is my blood pressure?
  • Do I have significant amounts of protein in my urine? Is anything being done about that?
  • Do I have to modify my diet?

Referral
One of the most crucial interventions to carry out when managing people with CKD is to identify when referral to secondary care is warranted. This is important because the renal team needs at least one year to prepare people both physically and emotionally for dialysis. If patients are not referred in good time they are less likely to receive interventions that could alter the progression of CKD, such as optimum blood pressure control, have a worse clinical state at the start of dialysis, have longer hospitalisation and poorer survival. A summary of when to refer people for specialist assessment is shown in Table 4.

[[Tab 4 CKD]]

Conclusion
Recent QOF targets for CKD and the publication of NICE guidance for CKD have resulted in changes to the management of CKD in primary care. Primary care nurses are well placed to inform people about the condition and to provide optimum care to slow down CKD progression, through good blood pressure control, protein quantification and lifestyle modification.
 
References
1. National Institute for Health and Clinical Excellence (NICE). Early identification and management of chronic kidney disease in adults in primary and secondary care. NICE clinical guideline 73. London: NICE; 2008.
2. Levey AS, Coresh J, Greene T et al. Using standardized serum creatinine values in the modification of diet in renal disease study equation for estimating glomerular filtration rate. Ann Intern Med 2006;145(4):247-54.
3. De Lusignan S, Chan T, Gallagher H et al. Chronic kidney disease management in southeast England: a preliminary crosssectional report from the QICKD - Quality Improvement in Chronic Kidney Disease study. Primary Care Cardiovascular Journal 2009;2(1):33-39.
4. Wali RK, Henrich WL. Chronic kidney disease: a risk factor for cardiovascular disease. Cardiol Clin 2005;23(3):343-62.

Resources
Resources for patients
Information sheet to give to patients
Kidney Damage and What it Means to You
W: www.bjpcn-cardiovascular.com/download/3337

Department of Health leaflet on proteinuria
W: www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPoli...

Kidney Research UK/British Renal Society
Living with Kidney Disease: what you should know
W: www.kidneyresearchuk.org/shopping/living-with-kidney-disease-dvd.php

National Kidney Federation
W: www.kidney.org.uk/Medical-Info/index.html
Leaflets can be downloaded or ordered by telephone

Resources for professionals
Chronic Kidney Disease: a Guide for Primary Care
An advanced online educational resource
W: www.ckdonline.org

British Renal Society
Resources for primary care - click on CKD Forum
W: www.britishrenal.org

Quality Improvement in Chronic Kidney Disease
A three-year quality improvement study exploring the best ways of managing CKD in primary care
W: http://kidneyresearchuk.org/ckd-qi