This site is intended for health professionals only

Clinical: Understanding chronic kidney disease

Over two million people in the UK have been diagnosed with moderate to severe (stages 3-4) chronic kidney disease (CKD) by their GP, but it is estimated that a further one million remain undiagnosed because often few or no symptoms present until the later stages
of the disease.1

CKD is defined as abnormalities in imaging tests, blood or urine composition or a low estimated glomerular filtration rate (eGFR) A decrease in eGFR

CKD stage 3-5 prevalence is higher in women than in men – 7.4% versus 4.7%3 – with a clear association with increasing age: 1.9% of people aged under 65 have the condition compared with 13.5% aged between 65-74 and 32.7% aged 75 and over.3
In 2011/12, 1.9 million people aged 18 and over were included in the Quality and Outcomes Framework (QOF) CKD registers, equalling 4.3% of the population of this age group.3

To help identify CKD earlier, the Health Foundation4 is funding a quality improvement initiative (ASSIST-CKD). This highlights people with declining kidney function to laboratory staff, who alert GPs to ensure they are aware of the decline and can consider referral to a nephrologist. Timely referral to secondary care can reduce the rate of decline and delay the need for dialysis or a kidney transplant.4

Symptoms

Primary care nurses should be aware of the symptoms of CKD, as it may progress without symptoms for a long time because it can be masked by other long-term conditions and co-morbidities:

  • Fatigue and weakness.
  • Headaches.
  • Numbness in hands or feet (peripheral neuropathy).
  • Disturbed sleep.
  • Loss of appetite.
  • Nausea and vomiting.
  • Need to urinate frequently.
  • Fluid retention (swollen legs/puffy eyes).
  • Itching.
  • Easy bruising.
  • Pale skin.
  • Restless legs.
  • Hypertension.
  • Decreased libido.

Who is at risk of developing CKD?

Diabetes is now the most common cause of advanced kidney disease in the UK, with diabetes being recorded as the primary diagnosis for patients commencing renal replacement therapy.5 There has been an increase of 4.5% between 2013-14, a 16.1% increase of all prevalent patients, compared with 13.5% in 2006.6

Having CKD and diabetes combined increases cardiovascular risk, so preventing cardiovascular complications is a major focus of management of modifiable risk factors. Patients can take simple measures to alter their lifestyle – increasing exercise, reducing bodyweight and improving nutritional intake can reduce the incidence of Type 2 diabetes and slow progression of CKD.6

People with CKD should continue to have their diabetes managed in primary care and be empowered to self-care with any changes in medication and treatment being shared with both renal and primary care. Nurses can play a big role in this.

Who should have their kidney function checked?

People with these long-term conditions are at risk of developing CKD, and should have their kidney function checked annually using eGFR creatinine and albumin creatinine ratio (ACR) tests:

  • Diabetes.
  • Hypertension and cardiovascular disease (eg ischaemic heart disease, chronic heart failure, peripheral vascular disease or cerebral vascular disease).
  • Structural renal tract disease, recurrent renal calculi or prostatic hypertrophy.
  • Multisystem diseases with potential kidney involvement (for example, systemic lupus erythematosus).
  • Family history of stage 5 CKD or hereditary kidney disease.
  • Long-term use of non-steroidal anti-inflammatory drugs (NSAIDs).

People who have experienced an episode of acute kidney injury (AKI) and are discharged back to the GP should be monitored for at least two to three years (even if creatinine has returned to baseline) and advised that they are at increased risk of developing CKD or it progressing if they are already known to have CKD. Information for patients on AKI is available from the British Kidney Patient Association.6

Measuring kidney function

Reporting of eGFR alongside serum creatinine levels has been embedded in practice since 2006, along with the classification of stages 1-5 CKD using the modification of diet in renal disease (MDRD) equation.7

NICE1 has recommended that the chronic kidney disease epidemiology collaboration (CKD-EPI) creatinine equation be used if there is a need to confirm CKD in someone with an eGFR creatinine 45-59ml/l/min/1.73m2 for at least 90 days and no proteinuria. This is an attempt to prevent over-diagnosis of CKD – particularly in the elderly. However, this test is not yet available in all laboratories and most use the MDRD equation.

Proteinuria

The terms proteinuria and albuminuria are often used interchangeably. NICE guidance1 has chosen to use the term proteinuria, recommending ACR as the best means of measuring this. The term microalbuminuria, used to describe an ACR range 3-70mg/mmol, is now obsolete. ACR has been categorised into A1, A2, A3 according to levels of proteinuria.

Previously, the upper limit of the normal ACR range differed in males and females, but this has now been standardised to >3mg/mmol for both. It is important to remember that exercise and increased activity can result in a misleadingly raised ACR. Nurses should be aware of this when collecting urine samples. If an ACR result of >3mg/mmol is received on a non-morning sample, the test should be repeated using an early-morning sample. However, if the result is >70mg/mmol, there is no need to repeat it. A confirmed ACR of >3mg/mmol should be regarded as clinically significant proteinuria and trigger regular monitoring. A combination of ACR and eGFR categories should be used to classify CKD .7

CKD stages 1-5 are now classed as G1-G5. The frequency of monitoring should be tailored according to: 

  • Underlying cause.
  • Past patterns of eGFR and ACR.
  • Co-morbidities.
  • Changes in treatment (ACE inhibitors, angiotensin receptor blockers, NSAIDs, diuretics).
  • Intercurrent illness.
  • Whether the patient chooses to have renal replacement therapy or be treated conservatively (no dialysis or transplant).
  • Stage and progression of CKD and monitoring of other long-term conditions such as diabetes and hypertension.

Collaborative working with renal teams

Practice and community nurses are experienced in the management of long-term conditions in primary care. As CKD often sits alongside an existing long-term condition such as diabetes, heart failure and hypertension, the management of these patients has similar components, such as offering lifestyle guidance (stop smoking, exercise, reduce weight, improve blood glucose control if diabetic and record own blood pressure with the aim to decrease cardiovascular risk). All these measures slow the progression of CKD and prolong the time it takes to reach the need for dialysis.

Blood pressure management in CKD is based on NICE hypertension guidance.8 For people with CKD without diabetes and ACR 70mg/mmol is 120-129/80mmHg. Be aware that a combination of ACE inhibitor and angiotensin receptor blockers should not be used.

Nurses should always check the anti-hypertension medication of patients and any changes in prescription.

It may be helpful to arrange to spend time in one of the renal clinics, particularly if you are a non-medical prescriber, to expand your knowledge of CKD in practice and meet members of the renal multidisciplinary team.

Patients with stages 3B-5CKD will be seen regularly in the renal clinic, but the majority of their care can be delivered in the community. The renal team may request follow-up blood tests, blood pressure monitoring, assistance with medication reviews, fluid balance and diabetes management. The majority of renal units have a team of nurse specialists who liaise with primary care nurses. If there are any concerns about potassium levels in patients receiving ACE inhibitors, the renal dietitian can be contacted for advice.

Case Study 

 

Mrs A is 75 years old and has had hypertension for 12 years. She does not have diabetes and has no other significant past history. She has been on the CKD register for four years. Her eGFR has declined from 55ml/min to 41ml/min during this time. She also has proteinuria; her latest ACR is 32mg/mmol. Her BP is 135/80mmHg taking amlodipine 5mg. She attends the GP practice for her routine monitoring visit. Which of these statements is true?

a) Because she has progressive loss of renal function, she should be referred to a specialist for further investigation and management.

b) Because she has proteinuria, she should be offered an ACE inhibitor instead of her current drugs.

c) Her eGFR, ACR and blood pressure should be reviewed every six months.

 

(Answer b & c)

 

 

References

1.     BMJ National CKD Audit.ckdaudit.org.uk  (accessed 5 December 2016).

2.     NICE. Chronic Kidney Disease in Adults; Assessment and management. July 2014; updated January 2015; nice.org.uk/guidance/cg182 (accessed 5 December 2016).

3.     Public Health England Chronic Kidney Disease Prevalence Model October 2014. PHE publications gateway number: 2014386.

4.     ASSISI-CKD. UK Renal Registry. renalreg.org/research/assist-ckd  (accessed 5 December 2016).

5.     UK Renal Registry 2015; 18th Annual Report of the Renal Association; Nephron2016;132(suppl1):41-68.

6.     British Kidney Patient Association.britishkidney-pa.co.uk/images/downloads/patient_information_leaflets/AKI_leaflet.pdf (accessed 4 January 2017).

7.     Levey AS, Bosch JP, Lewis JB et al. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Annals of Internal Medicine1999;130;461-70; ncbi.nlm.nih.gov/pubmed/10075613  (accessed 5 December 2016).

8.     Jenkins K. NICE guidance update on chronic kidney disease classification. Journal of Renal Nursing2014;6:185-7.

Suggested Further Reading:

Understanding Chronic Kidney Disease: A Guide for the Non-Specialist Robert Lewis M&K Publishing 2012

Oxford Handbook of Renal NursingMahon A, Jenkins K, Burnapp L; Oxford University Press 2013

Useful websites

britshrenal.org

anaemia nurse.org