What practice nurses need to know about the NICE chronic kidney disease guidelines

Chronic kidney disease (CKD) is increasing in prevalence as the UK and world population ages (Bikbov et al, 2020). Good management of CKD can both slow down the progression of disease and reduce mortality in people affected. This article will describe what CKD is, its main causes, presenting signs and symptoms, as well as how it is diagnosed and classified. The management of CKD in primary care, based on the guidelines contained in the most recent update of the National Institute for Health and Care Excellence (NICE, 2021a), will also be reported.

Definition

Chronic kidney disease (CKD) is defined as a reduction in kidney function, or damage to kidney structure, which has persisted for greater than 3 months and which is associated with other health-related issues (NICE, 2021b). By its nature, CKD is incurable and progressive, and while it is amenable to treatment and management, it is associated with a high level of mortality (Swartling et al, 2021).

Causes

While there are many causes of CKD, the most prevalent in western societies, including the UK, are diabetes and hypertension. The prevalence of CKD among people living with diabetes being 30–40% (Winocour, 2018).

Notably, hypertension is both a cause and effect of CKD and contributes to disease progression in all aetiologies. The management of hypertension is therefore a central feature of the management of CKD from all causes (Pugh et al, 2019).

NICE (2021b) identify several causes of CKD, while the general advice about managing the progression of CKD is generic, ie mainly focussed on hypertension management, understanding the cause may be important in diseases for which there are specific treatments, eg immunosuppression or the relief of obstruction. Key causes of CKD include:

• Intrinsic kidney damage associated with:
• Hypertension giving rise to hypertensive nephropathy
• Diabetes causing diabetic nephropathy
• Glomerular disease eg glomerulonephritis and HIV-associated nephropathy.
• The use of nephrotoxic drugs such as:
• Angiotensin-converting enzyme inhibitors (ACEI)/angiotensin II receptor blockers (AIIRBs)
• Immunosuppressants eg ciclosporin or tacrolimus
• Long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) eg ibuprofen.
• Diseases which contribute to obstructive uropathies including:
• Structural abnormalities of the renal tract
• Neurogenic bladder
• Prostatic disease
• Urinary tract calculi (stones).
• Systemic disease which has kidney involvement including:
• Systemic lupus erythematosus (SLE)
• Myeloma
• Vasculitis.
• Familial or hereditary diseases which affect the kidney including:
• Alport syndrome
• Autosomal dominant polycystic kidney disease.
• Cardiovascular disease affecting the renal vasculature for example:
• Renal artery stenosis
• A history of acute kidney injury (AKI).

It is important primary care professionals recognise that an individual may have more than one cause of CKD, or that the cause of CKD may not always be as obvious as it seems. For example, hypertension in a patient newly presenting with CKD does not mean that it predated the CKD since, as we have seen, hypertension is both a cause and effect of CKD.

Signs and symptoms

The signs and symptoms of CKD vary widely because of the aetiology of the disease, the severity of the disease, the characteristics of the person with CKD, as well as the presence of concomitant disease. NICE (2021b) recognise that many individuals are asymptomatic for CKD in its early stages but that it should be among the issues considered in people who present to general practice with such diverse signs and symptoms as:

• Lethargy
• Itchiness
• Breathlessness
• Sleep disturbance
• Appetite and weight loss
• Changes in urinary habit, eg polyuria, oliguria, nocturia, signs of outflow obstruction
• Uraemic odour
• Pallor
• Cognitive impairment
• Peripheral oedema
• Frothy or bloodied urine.

CKD may also be noted as an incidental finding when investigating patients presenting with other issues. Incidental finding such as proteinuria should not just be pigeonholed as being urinary tract infection (UTI)-related without laboratory confirmation, and should trigger considerations of CKD. Similarly, patients who have a history of hypertension and/or diabetes should be regularly tested for CKD as part of routine screening (NICE, 2021c), while CKD should be high on the list of differential diagnoses in patients with a suggestive family history.

Diagnosis

Gaining a diagnosis of CKD does not rely on understanding the cause in the first instance, although it is important to quickly understand the aetiology of any kidney disease so that acute kidney injury (AKI) can be excluded. This is especially important because, as its name suggests, AKI is reversible although it can co-exist with CKD and/or be a risk factor for the development of CKD (Heung et al, 2016; NICE, 2019a).

When the practice nurse suspects that a patient may have CKD, they should investigate both the individual's urine and blood. A serum creatinine estimated glomerular filtration rate (eGFR) should be the undertaken with the patient having fasted from meat for at least 12 hours prior to the test. NICE (2021b) recommend:

• Where the eGFR is less than 60 ml/min/1.73 m², the test should be repeated within 2 weeks. This is unless a prior test shows the eGFR to be stable
• If after a repeat test the eGFR remains less than 60 ml/min/1.73 m², and there is nothing to suggest rapid deterioration, which may be suggestive of AKI, the eGFR test should be repeated within 3 months.

Practice nurses should be aware that the eGFRs of people who are particularly muscular, use protein supplements, are pregnant, have significant oedema or are malnourished need interpreting with caution. Similarly, patients of Asian and Chinese origin also require their eGFR to be interpreted carefully. This is why recording of the patient ethnic origin on test request forms is important.

Investigation of urine can start in the surgery with a simple dip test which can be used to exclude both the presence of a UTI, and haematuria which may be associated with urological cancer.

The undertaking of an early morning urine sample for an albumin:creatinine ratio (ACR) is also a requirement of CKD screening. NICE (2021b) identify:

• A result of less than 3 mg/mmol indicates no proteinuria and there is no action required
• A result between 3 and 70 mg/mmol, requires repeat testing within 3 months
• If the result is 70 mg/mmol or more, a repeat test is not needed as this indicates significant proteinuria. Elevated levels of proteinuria may be indicative of the need for tighter blood pressure control, often using ACEI or AIIRBs. Elevated levels of proteinuria which are sustained and not associated with UTI, menstruation or strenuous exercise, may be indicative of the need to refer the patient for nephrological care.

Classification

CKD severity is staged according to the extent of decrease in the eGFR and increase in the ACR. This means that CKD is classified by eGFR and ACR category, for example a mild to moderate decrease in eGFR accompanied by a moderate increase in ACR is classified as G3aA2 as indicated in Table 1.

Notably, the risk of CKD and disease progression increases dramatically for the patient from G3a and A2 onwards and the practice nurse should therefore be monitoring their condition carefully.

Management

As CKD is progressive from mild disease right through to kidney failure requiring dialysis or transplantation, the role of management in primary care is to:

• Identify CKD
• Monitor CKD for progression
• Slow disease progression
• Manage signs and symptoms
• Educate and support the patient
• Refer for specialist care when necessary.

Identification of CKD is undertaken as described above and includes screening of high-risk individuals, eg people living with diabetes and/or hypertension, as well as incidental diagnosis following self-presentation of an individual to the surgery.

NICE guidance (2021a) on monitoring the progression of CKD includes undertaking further blood and urine testing as described between once a year for mild disease which is slowly, or not, progressing, through to four-times a year for severe or rapidly progressing disease (defined as a 25% or 15 ml/min/1.73 m² change in eGFR within the year).

Slowing disease progression in CKD universally includes the management of hypertension. NICE 2021a recommend:

• A systolic blood pressure below 140 mmHg in patients with an ACR under 70
• A systolic blood pressure below 130 mmHg in patients with an ACR over 70.

This is achieved by following NICE's (2019b) guideline on management of hypertension for adults and should include the use of an ACEI or AIIRB of the highest tolerable dose where the patient has hypertension and an ACR in excess of 30 mg/mmol and/or diabetes. The use of any renin–angiotensin system antagonists should be undertaken with caution where the patient has an elevated serum potassium, and monitoring of the patient's eGFR is indicated. The renin–angiotensin system antagonist should be stopped where there is an unexplained decline in kidney function of 25% or more.

Since cardiovascular disease is a frequent concomitant of CKD (BMJ, 2021), the use of atorvastatin is recommended for primary or secondary prevention of cardiovascular disease in any individual living with CKD (NICE, 2016). This includes dose increases to achieve a greater than 40% reduction in non-HDL cholesterol where the patient's eGFR is 30 ml/min/1.73 m² or more. Where the eGFR is less than 30 ml/min/1.73 m², the use of higher dosing must be discussed with a nephrologist. Similarly, antiplatelet or anticoagulants use is indicated for secondary prevention (NICE, 2021d).

Practice nurses should be aware of the recommendations for the use of sodium-glucose cotransporter-2 inhibitors (SGLT2 inhibitors) in people living with diabetes and CKD. Current advice is that where the patient has an ACR in excess of 30 mg/mmol and they meet the licensing criteria these may be used (although this advice is currently under review and does not include all SGLT2 inhibitors) (NICE, 2021a).

Other care of people with CKD in general practice may be subject to local shared care protocols and include the management of issues such as anaemia and hyperphosphataemia alongside kidney and dietary care professionals.

General practice is a good place for the education and support of people living with CKD to begin. This might include information specific to their disease type, if known, as well as the nature of CKD in general and the sorts of choices around renal replacement therapies/conservative management the patient might face in the future. The practice nurse is also well placed to encourage lifestyle interventions for the patient which according to NICE (2021a) should include increased exercise, weight loss and smoking cessation where indicated.

Referral for nephrological care should be timely and support the necessity for specialist input into diagnosis, CKD stabilisation, the management of CKD sequalae (eg hypertension and anaemia), as well as education and preparation for renal replacement therapy/conservative management. NICE (2021a) identify the need for referral when the patient has:

• A greater than 5%, 5-year risk of requiring renal replacement therapy
• An ACR of 70 mg/mmol or more (and not diabetic)
• An ACR of 30 mg/mmol or more and haematuria
• A 25% or more sustained decrease in eGFR within the year
• A sustained decrease in eGFR of 15 ml/min/1.73 m² or more per year
• Poorly controlled hypertension on a minimum of four antihypertensive medicines
• Assumed, or actual, rare or genetic causes of CKD or renal artery stenosis.

Referral to the kidney care team can, in many instances, be moderated for the patient by shared care protocols where the individual is followed up in general practice and results shared between there and the nephrology clinic.

Conclusion

This article has identified the role of the practice nurse in identifying, monitoring and managing CKD in primary care. Practice nurses should be familiar with screening regimes for CKD as well as the guidance for ordering of CKD testing and ongoing monitoring. The role of the nurse in managing hypertension, especially in general practice, is well established and is vital in the ongoing management of CKD, slowing down disease progression and minimising the cardio- and cerebrovascular risks it poses.

Practice nurses need to be familiar with the various guidance from NICE and how these correspond with each other in the ongoing management of people with CKD. While primary care is pivotal in managing the majority of people living with CKD, practice nurses should also identify and work with their local kidney care team under shared protocols, as well as understanding when referral for nephrological specialist care is required.

KEY POINTS:

• Chronic kidney disease (CKD) is highly prevalent in the community
• Practice nurses play a key role in identifying and managing CKD
• Monitoring of CKD progression requires both estimated glomerular filtration rate (eGFR) and albumin:creatinine ratio (ACR) testing
• The universal means of slowing CKD progression is good blood pressure control
• Practice nurses should recognise when referral for nephrological care is indicated

CPD reflective practice:

• List some of the main causes of chronic kidney disease (CKD) in the UK
• Reflect on the signs and symptoms of CKD and why you might suspect it in a patient presenting feeling unwell
• Consider how you might support patients to reduce the rate of progression of CKD
• Describe the features of CKD which might prompt you to refer your patient to the nephrology clinic