Chronic kidney disease (CKD) is a growing health concern and the majority of this patient group are being cared for in primary care. Primary care nurses play a key role in ensuring patients with CKD receive appropriate education and health maintenance. This article explores who is at risk of developing CKD, how it is detected, long-term monitoring and when to refer for specialist assessment.
What is CKD?
Chronic kidney disease is defined as irreversible kidney damage leading to structural abnormality with proteinuria and/or haematuria, and/or glomerular filtration rate (GFR) <60ml/min/1.73m².1 Glomerular filtration rate describes the flow rate of filtered fluid through the kidneys and is considered an accurate measure of overall kidney function. The following groups of people are at risk of developing CKD and therefore should be monitored at least annually.1
– Diabetes mellitus.
– Cardiovascular disease or cardiovascular risk factors.
– Structural renal tract impairment.
– Families with known CKD stage 5 or hereditary kidney disease.
– Multi-system diseases with potential for kidney involvement.
– Opportunistic or persistent haematuria or proteinuria in the absence of urological cause.
– Nephrotoxic drugs.
– Treatment with angiotensin-converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARBs) or diuretics.
– Recurrent urinary stones (>1 episode per year).2
Detection of CKD
To screen and classify as having CKD you need to obtain a minimum of two GFR estimations separated by a 90 day period. In people with a new finding of reduced estimated glomerular filtration rate (eGFR), repeating the eGFR within two weeks is recommended to exclude other causes of acute deterioration, for example, acute kidney injury or initiation of ACE inhibitor/ARB therapy.1 Once classified as having CKD and placed on the CKD register, the priority is to prevent progression. Progression is defined as a decline in eGFR of more than 5ml/min/1.73m² within one year, or more than 10ml/min/1.73m² within five years and requires three independent eGFR estimations over at least a 90-day period.1
Monitoring patients with CKD requires regular blood and urine testing. The frequency and type of bloods that are required changes throughout the stages and it is important to get this right (see Table 1). When testing blood, it is important to remember that prior to the test, patients should be asked not to exercise or eat meat for 12 hours beforehand.1 It is also recommended that blood samples should be processed no longer than 12 hours from venepuncture. When testing for microalbuminuria, an early morning urine sample is preferable, and testing should be avoided in an acute illness or menstruation.2
Controlling blood pressure in renal disease is thought to be beneficial in protecting long-term kidney function and slowing of progression. People are often unaware of the link between kidney disease and hypertension, and as such require education in understanding how lowering blood pressure can protect their kidneys from further damage. The National Institute for Health and Care Excellence (NICE) recommend a systolic blood pressure of 120-139mmHg and a diastolic pressure less than 90mmHg. However, a different target is required if the patient is either diabetic and/or has significant albuminuria.1
Microalbuminuria, quantified by urinary albumin creatinine ratio (uACR) is known to be significant from a cardiovascular point of view in people without diabetes at a level of 2.5mg/mmol (male) or 3.5mg/mmol (female). However in the presence of diabetes it becomes significant at this level from both a cardiovascular and renal perspective and blood pressure should range from 120-129mmHg systolic and <80mmHg diastolic. These targets also apply should the uACR report >70mg/mmol.1 Similarly, eGFR classification of microalbuminuria requires two samples separated by at least two weeks.2 Again samples should not be included in diagnosis of microalbuminuria in the presence of infection.
In addition achieving good glycaemic control, managing any cardiovascular risk factors will contribute to the preservation of kidney function and should play an integral part of an individual’s treatment plan if applicable.
Despite best intentions, a proportion of people with CKD will see their condition progress and as a result will need specialist assessment. Following discussion, people with the following should be considered for referral into secondary care specialist renal services:
CKD stage 4 and 5 (with or without diabetes).
Heavy proteinuria (ACR >70mg/mmol) unless already known to be due to diabetes and being treated accordingly.
Proteinuria (>30mg/mmol) together with haematuria.
Progressive CKD (>5ml/min/1.73m² in one year or 10ml/min/1.73m² within five years).
Resistant hypertension: if using at least four anti-hypertensive drugs without success.
People with or suspected of having rare or genetic causes of CKD.
Suspected renal artery stenosis.
Role of primary care nurses
Primary care nurses play a pivotal role in the management of patients with CKD. Helping and enabling people to be aware of their condition, and educating them to make informed decisions about long-term treatment is thought to be beneficial. Enhancing self-management can be achieved by:
Educating patients on the importance of blood pressure control ensuring they are aware that reducing raised blood pressure is a key factor in preventing progression of CKD.
Encourage home blood pressure monitoring where appropriate.
Education on maintaining a good glycaemic control to slow progression of CKD.
Advice on healthy eating and exercise.
Chronic kidney disease, if not managed carefully, can become progressive; therefore it is up to health care professionals to ensure that all is realistically done to slow down the process. Effective monitoring according to disease stage, health education and appropriate timely referral to specialist services, can benefit individuals with CKD in terms of improving long-term outcomes.
However early detection is paramount if we are to offer patients some respite from another long term condition.