Chronic kidney disease and older people—implications of the publication of the Part 2 of the National Service Framework for Renal Services
Chronic kidney disease (CKD) is a long-term condition that can be progressive but often is not. It is primarily a disease of older people, and the extent of this is only just being recognised. The first true population data of incidence 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 m2 to be 4.3% of the total population but 25% of those over 70 years (even though the study did not include institutionalised older people). A study in the South East of England [2] which surveyed laboratory records looking at patients with serum creatinine >135
mol/l in women and >180 mol/l in men (with a median GFR of 28.5 ml/min/1.73 m2) found the prevalence of significant CKD to be 5,554 per million population, 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 those not referred were over 70 years, with 66% being over 80 years (Figure 2). The proportion of blood samples requested in the unreferred group by geriatricians was over 20%, second only to general practitioners (GPs). We geriatricians are, therefore, already seeing many patients with CKD and often managing them without referral to renal services. We have to ensure that we are offering the most appropriate investigations and treatments.
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What are the advantages of identifying and treating patients with CKD?
First, early identification of CKD is important as it allows appropriate measures to be taken to combat the major risk of illness or death because of cardiovascular disease. Second, there is good evidence now that appropriate treatment of patients with CKD can slow or prevent progression of their disease towards more serious CKD or established renal failure [3]. Third, there is also evidence that appropriately treating CKD can improve quality of life, for example using erythropoiesis-stimulating agents (ESAs) in renal anaemia. Finally, as we read in Age and Ageing recently, many older people are being referred and accepted onto dialysis [4]. Late referral of patients for dialysis either because of failure to recognise the severity of the disease or because of failure to consider this as an option leads to poorer outcomes in terms of both early mortality and hospitalisation rates [5]. It is therefore important to recognise and treat CKD early.
The National Service Framework (NSF) for Renal Services has been published in two parts. The first (published in 2004) [6] concentrated on established renal failure, dialysis and transplantation. The second [7] was published in February 2005 and contains work on CKD, acute renal failure and end-of-life care in renal disease. The section on CKD is divided into two quality requirements—one on the prevention and detection of CKD and the second on the minimisation of the progression and consequences of CKD. It highlights the high incidence of CKD in older people and specifically states ‘they need packages of care which co-ordinate and personalise their treatment, without requiring them to attend different clinics at different times in different places’. Guidelines for the identification, management and referral of adults with CKD [8] have been developed alongside the NSF by the Royal College of Physicians and the Renal Association (RCP/RA Guidelines). These provide advice on managing CKD outside of the renal unit to slow progression and also give advice on appropriate referral to renal services. A desktop guide, designed for the use of GPs and non-renal physicians, is being developed to aid us in providing the best evidence-based care.
It has long been known that using serum creatinine to identify reduced renal function is inaccurate, particularly in older people. It is possible to have lost over half your renal function and still have a serum creatinine in the normal range. Creatinine clearance, using 24-h urine collections, is also fraught with difficulties leading to inaccuracies. The NSF for Renal Services has recommended the use of formula-based estimation of glomerular filtration rate (eGFR). There are two commonly used formulae, Cockcroft and Gault and the MDRD formulae, both of which have been shown to be as accurate in older people as in younger people [9]. The NSF calls for laboratories in England to issue eGFR on all samples requesting creatinine, and the guidelines have recommended that four-variable MDRD be used. This will ensure that older people with CKD will be recognised, enabling appropriate treatments to be initiated and drug doses to be adjusted according to their kidney function.
Cystatin C is a newer marker of kidney disease and has been shown to be more sensitive than creatinine at highlighting kidney disease in older people [10] and has been found to be a stronger predictor of risk of death and cardiovascular deaths in older people [11].
The NSF has also adopted the international classification of CKD developed by US National Kidney Foundation [12] as illustrated in Table 1.
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In the earlier stages of CKD (especially stage 3), the most important interventions are those which are shown to reduce the risk of cardiovascular disease, such as correcting lipid abnormalities and advising patients to lose weight and stop smoking. However, in CKD, other special considerations need to be taken into account. When treating hypertension in patients with CKD and proteinuria (confirmed on two occasions by protein to creatinine or albumin to creatinine ratio), there is strong evidence that using angiotensin-converting enzyme inhibitors or angiotensin receptor blockers slows the rate of decline of CKD. Careful monitoring of serum potassium and kidney function (before initiation 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, and 27% of those not referred to renal teams in the East Kent Study had Hb levels below 11 g/dl. The treatments (after exclusion of other causes) should include intravenous iron and ESA. The National Institute of Clinical Excellence is currently developing guidelines on the treatment of anaemia in CKD, which are due to be published early in 2006.
Renal bone disease also starts in stage 3 CKD, and its significance is more important in older people because of the co-existing high incidence of osteoporosis in this group. Renal physicians advise investigating and treating renal bone disease before initiating bisphosphonate treatments. Persistent abnormalities of calcium and phosphate in the context of CKD indicate significant renal bone disease, and treatment should be discussed with renal teams. If calcium and phosphate are normal, parathyroid hormone should be measured. Simple advice is available in the RCP/RA Guidelines on how to manage the earlier stages of renal bone disease.
Acidosis associated with CKD does not often occur before stage 4 CKD, but simple oral treatment with sodium bicarbonate has been shown to improve nutrition, bone disease and quality of life.
What is the future of care for older people with CKD?
Patients with rapidly deteriorating renal function or those with potentially reversible causes of CKD should be identified and referred for assessment by nephrologists. Similarly, patients with stage 5 CKD, whether or not they would benefit from renal replacement therapy, should also be under the renal teams. The RCP/RA Guidelines also recommend that patients with stage 4 CKD should at least be discussed with renal teams, and a treatment plan should be agreed. Many of these patients, however, remain stable for long periods of time and are often seen in our outpatient clinics and on our wards.
For the larger number of older patients with stage 3 CKD, the main interventions are those that are already being performed in a structured way in primary care due to the General Medical Services contract and the NSFs on cardiovascular disease and diabetes. Special consideration of anaemia and renal bone disease could be undertaken either in primary or in secondary care, and simple guidelines are available to follow. However, for the older frailer patient with multiple co-morbidities and CKD, the input from geriatricians with expertise of comprehensive assessments and access to multidisciplinary teams would seem the ideal place to co-ordinate this care.
CKD is a disease of older people, and simple treatments can slow the progression of the disease and improve quality of life. The NSF for Renal Services highlights older patients with CKD and stipulates that treatments aimed to prevent and then treat CKD should be available to all. The best way to achieve this is not clear but geriatricians have an important role. The publication of the RCP/RA Guidelines gives us clear 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 and are ideally placed to offer good evidence-based treatments, particularly of those with multiple co-morbidities.
S.O’R was the British Geriatrics Society (BGS) representative on Part 2 of the NSF for Renal Services [7] and was also represented the BGS on the group that developed the RCP/RA Guidelines on management of CKD [8].
East Kent Hospitals NHS Trust, Canterbury, UK
Email: shelagh.o'riordan{at}ekht.nhs.uk
References
- CoreshJ, Astor B, Greene T, Eknoyan G, Levey AS. Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third national health and nutrition examination survey. Am J Kidney Dis 2003; 41: 1–12.[Web of Science][Medline]
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- Strippoli G, Craig M, Deeks, JJ, Schena FB, Craig JC. Effects of angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists on mortality and renal outcomes in diabetic nephropathy: systematic review. BMJ 2004; 329: 828.
[Abstract/Free Full Text] - Ronsberg F, Isles C, Simpson K, Prescott G. Renal replacement therapy in the over-80s. Age Ageing 2005; 34: 148–52.
[Abstract/Free Full Text] - Huisman RM. The deadly risk of late referral. Nephrol Dial Transplant 2004; 19: 2175–80.
- Department of Health. National Service Framework for Renal Services: Part 1 –Dialysis and Transplantation. 2004.
- Department of Health. National Service Framework for Renal Services: Part 2 – Chronic kidney disease, Acute Renal Failure and End of Life Care. 2005.
- Adults with chronic kidney disease: Guidelines for identification, management and referral. London: Royal College of Physicians (in press).
- Lamb EJ, Webb MC, Simpson DE, Coakley AJ, Newman DJ, O’Riordan SE. Estimation of glomerular filtration rate in older patients with chronic renal insufficiency: is the modification of diet in renal disease formula an improvement? J Am Geriatr Soc 2003; 51: 1012–7.[CrossRef][Web of Science][Medline]
- O’Riordan SE, Webb MC, Simpson DE et al. Cystatin C improves the detection of mild renal dysfunction in older patients. Ann Clin Biochem 2003; 40: 648–55.[CrossRef][Web of Science][Medline]
- Shlipac MG, Sarnac MJ, Katz R et al.. Cystatin C and the risk of death and cardiovascular events among elderly persons. N Engl J Med 2005; 352: 2049–142.
[Abstract/Free Full Text] - National Kidney Foundation. Clinical practice guidelines for chronic kidney disease: evaluation classification and stratification. Am J Kidney Dis 2002; 39: S1–S266.[CrossRef][Web of Science][Medline]
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  E. J. Lamb, M. C. Webb, and S. E O'Riordan Using the modification of diet in renal disease (MDRD) and Cockcroft and Gault equations to estimate glomerular filtration rate (GFR) in older people Age Ageing, November 1, 2007; 36(6): 689 - 692. [Full Text] [PDF]
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