A stable definition of chronic kidney disease improves knowledge and patient care
BMJ 2013; 347 doi: https://doi.org/10.1136/bmj.f5553 (Published 18 September 2013) Cite this as: BMJ 2013;347:f5553- Josef Coresh, professor1,
- Andrew S Levey, professor2,
- Adeera Levin, professor3,
- Paul Stevens, consultant nephrologist4
- 1Departments of Epidemiology, Medicine, and Biostatistics, Johns Hopkins University, Baltimore, MD 21287, USA
- 2Division of Nephrology, Tufts Medical Center, Boston, MA, USA
- 3Division of Nephrology, University of British Columbia, Canada
- 4Kent Kidney Care Centre, East Kent University Hospitals NHS Foundation Trust, UK
- coresh{at}jhu.edu
As co-chairs of the 2002 and 2012 guidelines on the definition and staging of chronic kidney disease (CKD) we wanted to clarify several areas of disagreement with the authors of the recent BMJ article.1
Firstly, the 2012 definition is the same as the 2002 one.2
Secondly, new data assembled through a global consortium including 50 cohorts and more than two million people overwhelmingly support an increased risk associated with the definition thresholds (estimated glomerular filtration rate <60 ml/min/1.73m2 and urine albumin to creatinine ratio >30 mg/g (>3 mg/mmol)) regardless of age, hypertension, and diabetes.3
Thirdly, CKD is associated not just with progression to end stage renal disease but with risk of concurrent complications (anaemia, hyperparathyroidism, hyperphosphataemia) and future events (acute kidney injury, cardiovascular disease, mortality, fractures, infections).2 4 5
Fourthly, reduced glomerular filtration rate and albuminuria are not symptomatic but direct measures of kidney function and damage. They are strongly associated with risk of complications (>1000-fold for end stage renal disease and >10-fold in combination for many complications). Fifthly, in an era of patient self management, it is important to use a consistent definition to help detect disorders of kidney structure and function with health implications. Failure to disclose the true state of a person’s health could be viewed as paternalistic and counterproductive.
Finally, the attitude that disease in older people should be ignored and untreated is disturbing. Better treatments for CKD are needed, but only a subset of patients need referral (box). Older people benefit from treatment of common conditions that are often labelled as an inevitable part of ageing. Examples include treatment of hypertension to reduce stroke, osteoporosis to reduce fractures, cataracts to restore vision, and prevention and treatment of myocardial infarction. The availability of some treatments and the need for additional ones to improve outcomes in CKD should be a call for action, not inaction.
2012 clinical practice guideline criteria for referral2
5.1.1: We recommend referral to specialist kidney care services for people with chronic kidney disease (CKD) in the following circumstances:
Acute kidney injury or abrupt sustained fall in glomerular filtration rate
Glomerular filtration rate <30 ml/min/1.73 m2 (categories G4-G5)*
Consistent albuminuria (urine albumin to creatinine ratio ≥300 mg/g (≥30 mg/mmol) or albumin excretion rate ≥300 mg/24 h, roughly equivalent to protein to creatinine ratio ≥500 mg/g (≥50 mg/mmol) or protein excretion rate ≥500 mg/24 h)
Progression of CKD (see recommendation 2.1.3 for definition)
Urinary red cell casts, red blood cell count >20 per high power field (sustained and not readily explained)
CKD and hypertension refractory to treatment with four or more antihypertensive agents
Persistently abnormal serum potassium
Recurrent or extensive nephrolithiasis
Hereditary kidney disease
5.1.2: We recommend timely referral for planning renal replacement therapy in people with progressive CKD in whom the risk of kidney failure within one year is 10-20% or higher†, as determined by validated risk prediction tools
*If this is a stable isolated finding, formal referral (formal consultation and ongoing care management) may not be necessary and advice from specialist services may be all that is needed to facilitate best care. This will be healthcare system dependent.
†The aim is to avoid late referral, defined here as referral to specialist services less than one year before start of renal replacement therapy.
Notes
Cite this as: BMJ 2013;347:f5553
Footnotes
Competing interests: JC has received honorariums for engaging in educational activities and a research grant from Amgen through his university. ASL has received grants through his university from Amgen, Pharmalink, and Gilead. AL has received consultancy fees from Abbott Laboratories and Merck; she also has grants through her institution from the Canadian Institutes of Health Research (CIHR), Kidney Foundation, Merck, and Ortho. PS chairs the National Institute for Health and Care Excellence 2013 Chronic Kidney Disease (CKD) Update Guideline Development Group. All the authors participated in CKD guideline development and CKD prognosis consortium research.
Full response at: www.bmj.com/content/347/bmj.f4298/rr/657022.