Prevention and early detection of chronic kidney disease (CKD)

Diagnosis and management of chronic kidney disease (CKD) in primary care

In February 2005, part two of the National Service Framework (NSF) for Renal Services was published. The number of people at increased risk of developing or having undiagnosed chronic kidney disease, especially those with diabetes or hypertension, has risen over the years and this is expected to continue. To date, prevention programmes have been non-existent.

CKD background

It is estimated that over 1.1 million patients require maintenance dialysis worldwide and expanding at a rate of 7% per year and, if the trend continues by 2010, the number will exceed 2 million. In the past there has not been a real focus on management and prevention of CKD, with the prevalence remaining largely unknown. In recent studies there has been an attempt to ascertain the true extent of CKD. In 2001, a study of laboratory results in the South East of England (a predominantly Caucasian population) found a prevalence of CKD (stages 3-5) of 5554 per million population (pmp), 85% were unknown to renal services.

Monitoring of kidney function has largely relied on serum creatinine measurement; However this may not give an accurate representation of kidney function. By the time the creatinine is elevated, there is may already be a 50% reduction in kidney function. The most effective way to assess renal function, and therefore gauge the need for further investigation or referral, is by using estimated GFR (eGFR), a formula-based calculation of glomerular filtration rate.

CKD is progressive, however, with good management (mainly focussing on blood pressure, lipid and glycaemic control, together with smoking cessation and avoiding nephrotoxic drugs), the progression can be slowed down. The K/DOQI has classified CKD into 5 stages based on eGFR:

Download table of classification of CKD.

An eGFR between 60-90 on it is own is not indicative of CKD, only a minority of people will stage 1or 2 will go on to develop more advanced kidney disease, with symptoms usually only appearing at stage 4.

The Renal Services NSF and the UK guidelines for Chronic Kidney Disease recommend universal measurement of eGFR (a formula-based calculation of glomerular filtration rate) in at-risk groups and early referral to a tertiary centre where required.

With these requirements in mind, we are now working to:

produce clear referral guidelines
manage the referrals better and reduce waiting times
improve accessibility to the Trust for our primary care colleagues.
Report estimated GFR on all U and E requests to the clinical chemistry department.

We have developed draft referral guidelines in collaboration with some local GPs. Click on the links below to see these draft guidelines.

Download CKD guidelines - updated March 07.

We have set up a nephrology screening programme, led by our Consultant Renal Nurse, to manage the predicted higher number of referrals. Any referrals to the renal unit for screening, that that can be safely and effectively followed up in primary care, will be managed jointly with the GP with an agreed management plan and ongoing support from the unit.

Please contact Dr Alistair Chesser, Consultant Nephrologist, by email alistair.chesser@bartsandthelondon.nhs.uk; or Althea Mahon, Consultant Nurse, on tel 020 7377 7000 ext 7366 at The Royal London Hospital, if you have any queries or comments.

Who should be screened for CKD?

There is no evidence that screening of the general population for CKD is warranted. Groups at particular risk should be identified and screened at least annually. These include:

All patients with known CKD
Hypertension
Unexplained oedema
Suspected heart failure
Known atherosclerotic disease
Suspected multisystem disease with possible renal involvement eg vasculitis, SLE
Diabetes
Bladder outflow obstruction
Neurogenic bladder
Urinary diversion surgery
Stone disease
Long term treatment with potentially nephrotoxic drugs (eg NSAIDs, lithium)

Screening should comprise at least:

Measurement of eGFR
Urine dipstick
Measurement of BP

What to do if an abnormal eGFR is discovered?

Rule out acute renal failure (ie repeat eGFR within 5 days unless previous tests of renal function are available). Refer nephrology urgently if ARF
Dipstick urine (and repeat a few days later after excluding UTI if abnormal)
Classify the stage of CKD using the table of classification of CKD.
- For CKD stages 1 and 2, follow CKD stages 1-2 management pathway
- For CKD stage 3, follow CKD stage 3 management pathway
- For CKD stage 4, refer nephrology
- For CKD stage 5, refer urgently to nephrology.

Diabetic patients with albuminuria or low eGFRs should be managed in conjunction with the local diabetic team, with close attention to glycaemic control, BP control and ACE inhibitors / ARBs if albuminuria. The same criteria apply to nephrology clinic referrals as for non-diabetic patients.

CKD referral letters – info required

Full past medical history
Details of all prior renal function tests
Full drug history
Social history
Results of renal ultrasound (UNLESS immediate/urgent referral and not practically possible)
Haemoglobin, calcium and phosphate
For diabetics: HbA1c, results of retinal screening, evidence or absence of other macro or microvascular complications

References:

Department of Health. The National Service Framework for Renal Services. Part Two: Chronic Kidney Disease, Acute Renal Failure and End of Life Care. COI: London, 2005.
Lysaght, M. Maintenance dialysis population dynamics: Current trends and long-term implications. J Am Soc Nephrol, 13: S37-40, 2002.
Xue, J, Ma, J. et al. A forecast of the number of patients with end-stage renal disease in the United States to the year 2010. J Am Soc Nephrol, 12: 2753-2758, 2001.
Webb, J.R., Young, A. et al. Unreferred chronic kidney disease: a longitudinal study. Am J Kidney Dis, 43, (5): 825-35, 2004.
Guidelines for Chronic Kidney Disease: Identification, management and referral. http://www.renal.org/JSCRenalDisease/JSCRenalDisease.html#Anchor-Recent-11481