Chronic Kidney Disease
CKD is characterised by a gradual and permanent loss of kidney function that worsens as it progresses from stages 1 to 5. One of the most common complications of CKD is anaemia. Anaemia in patients with CKD causes debilitating weakness and fatigue, altered cognitive function, and a negative impact on quality of life and wellbeing.1 Among other consequences of CKD, anaemia contributes to the development and progression of cardiovascular disease (CVD) and corresponding increases in hospitalisation, cost of care, and mortality.2,3
Patients with CKD are grouped into five stages, based on evidence of kidney damage and decreasing glomerular filtration rates (GFRs) (Figure 1).4 Stage 5 patients have a GFR <15 mL/min/1.73 m2 and require kidney replacement therapy, either dialysis or transplantation (Table 1).4 Kidney damage is usually diagnosed based on the presence or absence of certain markers: persistent proteinuria; abnormalities in urine sediment, blood, and urine chemistries; and abnormal findings on imaging studies.4,5
Figure 1. The CKD continuum
Table 1. Stages of CKD by GFR
|Stage||Description||GFR (mL/min/1.73 m2)|
|1||Kidney damage† with normal or ↑ GFR||≥90|
|2||Kidney damage with mild ↓ GFR||60–89|
|3||Moderate ↓ GFR||30–59|
|4||Severe ↓ GFR||15–29|
|5||Kidney failure||<15 or dialysis or transplant|
In 2002, the National Kidney Foundation of the United States called upon an international group of experts to develop guidelines, which provided a clear and simple definition of CKD and a 5-stage classification system developed through an evidence-based process and supported by existing literature (see Figure 1 and Table 1). CKD is defined by the occurrence of kidney damage or GFR <60 mL/min/1.73 m2 for ≥3 months. Disease staging is based on the GFR.4
1. Lefebvre P, Vekeman F, Sarokhan B, Enny C, Provenzano R, Cremieux PY. Relationship between hemoglobin level and quality of life in anemic patients with chronic kidney disease receiving epoetin alfa. Curr Med Res Opin. 2006;22:1929-1937.
2. Foley RN, Parfrey PS, Harnett JD, Kent GM, Murray DC, Barre PE. The impact of anemia on cardiomyopathy, morbidity, and and mortality in end-stage renal disease. Am J Kidney Dis. 1996;28:53-61.
3. Locatelli F, Pozzoni P, Tentori F, del Vecchio L. Epidemiology of cardiovascular risk in patients with chronic kidney disease. Nephrol Dial Transplant. 2003;18(Suppl 7):vii2-vii9.
4. National Kidney Foundation. K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Am J Kidney Dis. 2002;39(Suppl 1):S1-S266.
5. Johnson CA, Levey AS, Coresh J, Levin A, Lau J, Eknoyan G. Clinical practice guidelines for chronic kidney disease in adults: Part I. Definition, disease stages, evaluation, treatment, and risk factors. Am Fam Physician 2004;70:869-876.6.