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Age and Ageing2005; 34:546548 The Author 2005. Published by Oxford University Press on behalf of the British Geriatrics Society.doi:10.1093/ageing/afi181 All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org

Chronic kidney disease and older people

implications of the publication of the Part 2 ofthe National Service Framework for Renal

Services

Chronic kidney disease (CKD) is a long-term conditionthat can be progressive but often is not. It is primarily a dis-ease of older people, and the extent of this is only justbeing recognised. The first true population data of inci-dence and prevalence of CKD was published in the US [1],showing the prevalence of glomerular filtration rate (GFR)between 30 and 60 ml/min/1.73 m2to be 4.3% of the totalpopulation but 25% of those over 70 years (even thoughthe study did not include institutionalised older people).A study in the South East of England [2] which surveyedlaboratory records looking at patients with serum creati-nine >135 mol/l in women and >180 mol/l in men(with a median GFR of 28.5 ml/min/1.73 m2) found theprevalence of significant CKD to be 5,554 per millionpopulation, with an exponential rise in the older age group(Figure 1). The same study looked at those who were and

were not referred to the renal team: almost 90% of thosenot referred were over 70 years, with 66% being over 80years (Figure 2). The proportion of blood samplesrequested in the unreferred group by geriatricians was over20%, second only to general practitioners (GPs). We geria-tricians are, therefore, already seeing many patients withCKD and often managing them without referral to renalservices. We have to ensure that we are offering the mostappropriate investigations and treatments.

What are the advantages of identifying and

treating patients with CKD?

First, early identification of CKD is important as it allowsappropriate measures to be taken to combat the major riskof illness or death because of cardiovascular disease. Second,there is good evidence now that appropriate treatment ofpatients with CKD can slow or prevent progression of theirdisease towards more serious CKD or established renal fail-ure [3]. Third, there is also evidence that appropriately treat-ing CKD can improve quality of life, for example usingerythropoiesis-stimulating agents (ESAs) in renal anaemia.Finally, as we read in Age and Ageing recently, many olderpeople are being referred and accepted onto dialysis [4]. Late

referral of patients for dialysis either because of failure torecognise the severity of the disease or because of failure toconsider this as an option leads to poorer outcomes in termsof both early mortality and hospitalisation rates [5]. It istherefore important to recognise and treat CKD early.

National drivers

The National Service Framework (NSF) for Renal Serviceshas been published in two parts. The first (published in2004) [6] concentrated on established renal failure, dialysis

Figure 1.The prevalence of chronic kidney disease (CKD) per

million persons by age [2].

0

10000

20000

30000

40000

50000

60000

70000

80000

< 40 40-49 50-59 60-69 70-79 >80

Figure 2. Percentage of patients with chronic kidney disease

(CKD) referred to renal teams by age [2].

0

10

20

30

40

50

60

70

80

80

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and transplantation. The second [7] was published in February2005 and contains work on CKD, acute renal failure andend-of-life care in renal disease. The section on CKD isdivided into two quality requirementsone on the preven-tion and detection of CKD and the second on the minimi-sation of the progression and consequences of CKD. Ithighlights the high incidence of CKD in older people andspecifically states they need packages of care which co-ordi-

nate and personalise their treatment, without requiring themto attend different clinics at different times in differentplaces. Guidelines for the identification, management andreferral of adults with CKD [8] have been developed along-side the NSF by the Royal College of Physicians and theRenal Association (RCP/RA Guidelines). These provideadvice on managing CKD outside of the renal unit to slowprogression and also give advice on appropriate referral torenal services. A desktop guide, designed for the use of GPsand non-renal physicians, is being developed to aid us inproviding the best evidence-based care.

Diagnosing and staging CKD

It has long been known that using serum creatinine to iden-tify reduced renal function is inaccurate, particularly in olderpeople. It is possible to have lost over half your renal func-tion and still have a serum creatinine in the normal range.Creatinine clearance, using 24-h urine collections, is alsofraught with difficulties leading to inaccuracies. The NSFfor Renal Services has recommended the use of formula-based estimation of glomerular filtration rate (eGFR). Thereare two commonly used formulae, Cockcroft and Gault andthe MDRD formulae, both of which have been shown to beas accurate in older people as in younger people [9]. TheNSF calls for laboratories in England to issue eGFR on allsamples requesting creatinine, and the guidelines have rec-

ommended that four-variable MDRD be used. This willensure that older people with CKD will be recognised, ena-bling appropriate treatments to be initiated and drug dosesto be adjusted according to their kidney function.

Cystatin C is a newer marker of kidney disease and hasbeen shown to be more sensitive than creatinine at high-lighting kidney disease in older people [10] and has beenfound to be a stronger predictor of risk of death and cardio-vascular deaths in older people [11].

The NSF has also adopted the international classifica-tion of CKD developed by US National Kidney Foundation[12] as illustrated in Table 1.

Specific treatments of CKD

In the earlier stages of CKD (especially stage 3), the mostimportant interventions are those which are shown toreduce the risk of cardiovascular disease, such as correctinglipid abnormalities and advising patients to lose weight andstop smoking. However, in CKD, other special consider-ations need to be taken into account. When treating hyper-tension in patients with CKD and proteinuria (confirmedon two occasions by protein to creatinine or albumin to cre-atinine ratio), there is strong evidence that using angi-otensin-converting enzyme inhibitors or angiotensin

receptor blockers slows the rate of decline of CKD. Carefulmonitoring of serum potassium and kidney function (beforeinitiation and 2 weeks after initiation or change of dose)should take place, and a fall of GFR of 20% or more should

initiate consideration of investigation of renal artery stenosis.Anaemia associated with CKD begins in stage 3, and27% of those not referred to renal teams in the East KentStudy had Hb levels below 11 g/dl. The treatments (afterexclusion of other causes) should include intravenous ironand ESA. The National Institute of Clinical Excellence iscurrently developing guidelines on the treatment of anaemiain CKD, which are due to be published early in 2006.

Renal bone disease also starts in stage 3 CKD, and its sig-nificance is more important in older people because of theco-existing high incidence of osteoporosis in this group.Renal physicians advise investigating and treating renal bonedisease before initiating bisphosphonate treatments. Persist-ent abnormalities of calcium and phosphate in the context ofCKD indicate significant renal bone disease, and treatmentshould be discussed with renal teams. If calcium and phos-phate are normal, parathyroid hormone should be measured.Simple advice is available in the RCP/RA Guidelines on howto manage the earlier stages of renal bone disease.

Acidosis associated with CKD does not often occurbefore stage 4 CKD, but simple oral treatment with sodiumbicarbonate has been shown to improve nutrition, bone dis-ease and quality of life.

What is the future of care for older people

with CKD?

Patients with rapidly deteriorating renal function or thosewith potentially reversible causes of CKD should be identi-fied and referred for assessment by nephrologists. Similarly,patients with stage 5 CKD, whether or not they wouldbenefit from renal replacement therapy, should also beunder the renal teams. The RCP/RA Guidelines also rec-ommend that patients with stage 4 CKD should at least bediscussed with renal teams, and a treatment plan should beagreed. Many of these patients, however, remain stable forlong periods of time and are often seen in our outpatientclinics and on our wards.

Table 1. Classification of chronic kidney disease (CKD) [12]

aThe diagnosis of stage 1 and 2 CKD requires the presence of kidney damage

for 3 months, manifest by pathological abnormalities of the kidney or abnor-

malities in the composition of urine, such as haematuria or proteinuria, or

abnormalities in imaging tests either with (stage 2), or without (stage 1),

decreased glomerular filtration rate (GFR).

Stage Description

GFR, ml/min

/1.73 m2Population

prevalence (%). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1a Kidney damage with normal

or increased GFR90 3.3

2a Kidney damage with mildly

decreased GFR

6089 3.0

3 Moderately decreased GFR 3059 4.3

4 Severely reduced GFR 1529 0.25 Kidney failure (established

renal failure)

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For the larger number of older patients with stage 3 CKD,the main interventions are those that are already being per-formed in a structured way in primary care due to the GeneralMedical Services contract and the NSFs on cardiovasculardisease and diabetes. Special consideration of anaemia andrenal bone disease could be undertaken either in primary or insecondary care, and simple guidelines are available to follow.However, for the older frailer patient with multiple co-mor-

bidities and CKD, the input from geriatricians with expertiseof comprehensive assessments and access to multidisciplinaryteams would seem the ideal place to co-ordinate this care.

Conclusion

CKD is a disease of older people, and simple treatments canslow the progression of the disease and improve quality oflife. The NSF for Renal Services highlights older patientswith CKD and stipulates that treatments aimed to preventand then treat CKD should be available to all. The best wayto achieve this is not clear but geriatricians have an import-ant role. The publication of the RCP/RA Guidelines gives usclear guidance on how to treat this disease and could be used

to audit practice and improve treatments for older people.Geriatricians are already seeing many patients with CKD andare ideally placed to offer good evidence-based treatments,particularly of those with multiple co-morbidities.

Conflicts of interests

S.OR was the British Geriatrics Society (BGS) representa-tive on Part 2 of the NSF for Renal Services [7] and was alsorepresented the BGS on the group that developed theRCP/RA Guidelines on management of CKD [8].

References

1. Coresh J, Astor B, Greene T, Eknoyan G, Levey AS. Preva-lence of chronic kidney disease and decreased kidney function

in the adult US population: Third national health and nutritionexamination survey. Am J Kidney Dis 2003; 41: 112.

2. John R, Webb M, Young A, Stevens PE. Unreferred chronickidney disease: A longitudinal study. Am J Kidney Dis 2004; 43:82535.

3. Strippoli G, Craig M, Deeks, JJ, Schena FB, Craig JC.Effects of angiotensin converting enzyme inhibitors andangiotensin II receptor antagonists on mortality and renaloutcomes in diabetic nephropathy: systematic review. BMJ

2004; 329: 828.4. Ronsberg F, Isles C, Simpson K, Prescott G. Renal replace-

ment therapy in the over-80s. Age Ageing 2005; 34: 14852.5. Huisman RM. The deadly risk of late referral. Nephrol Dial

Transplant 2004; 19: 217580.6. Department of Health. National Service Framework for Renal

Services: Part 1 Dialysis and Transplantation. 2004.7. Department of Health. National Service Framework for Renal

Services: Part 2 Chronic kidney disease, Acute Renal Failureand End of Life Care. 2005.

8. Adults with chronic kidney disease: Guidelines for identifica-tion, management and referral. London: Royal College of Phy-sicians (in press).

9. Lamb EJ, Webb MC, Simpson DE, Coakley AJ, Newman DJ,ORiordan SE. Estimation of glomerular filtration rate in olderpatients with chronic renal insufficiency: is the modification ofdiet in renal disease formula an improvement? J Am GeriatrSoc 2003; 51: 10127.

10. ORiordan SE, Webb MC, Simpson DE et al. Cystatin Cimproves the detection of mild renal dysfunction in olderpatients. Ann Clin Biochem 2003; 40: 64855.

11. Shlipac MG, Sarnac MJ, Katz R et al.. Cystatin C and the riskof death and cardiovascular events among elderly persons. NEngl J Med 2005; 352: 2049142.

12. National Kidney Foundation. Clinical practice guidelines forchronic kidney disease: evaluation classification and stratifica-tion. Am J Kidney Dis 2002; 39: S1S266.

SHELAGHORIORDANEast Kent Hospitals NHS Trust, Canterbury, UKEmail: shelagh.oriordan@ekht.nhs.uk