Kidney function and chronic kidney disease
Chronic kidney disease is a major public health problem. It is estimated that 10% of all adults presenting to a general practice in Australia have chronic kidney disease, and 80% have at least one risk factor.1
Kidney function and ageing - inevitable decline?
In the Australian community, estimated glomerular filtration rate (eGFR) has been shown to decline by around 20 mL/min/1.73 m2 from 90 mL/min/1.73 m2 at age 40 years to 70 mL/min/1.73 m2 at age 80 years (median rate of decline).2 While this decline is common in older people and predictive of adverse clinical outcomes, a fall in GFR should not be considered an inevitable consequence of ageing.1
Diagnosing chronic kidney disease
Chronic kidney disease is diagnosed as either:1
- An eGFR <60 mL/min/1.73 m2 that is present for ≥ 3 months, with or without evidence of kidney damage.
- Evidence of kidney damage with or without decreased GFR that is present for ≥ 3 months as evidenced by the following, irrespective of the underlying cause:
- haematuria after exclusion of urological causes
- structural abnormalities (e.g. on kidney imaging tests)
- pathological abnormalities (e.g. renal biopsy).
What do the guidelines say?
It is now recommended by Australian and International guidelines that the stages of chronic kidney disease be based on the combined indices of:1
- Kidney function (reduced measured or estimated GFR)
- Kidney damage (albuminuria/proteinuria)
- Underlying diagnosis (hypertension, diabetic kidney disease)
For example, stage 2 chronic kidney disease with microalbuminuria secondary to diabetic kidney disease.
- Kidney Health Australia. Chronic kidney disease (CKD) management in general practice. 2nd edition. 2012. http://www.kidney.org.au//LinkClick.aspx?fileticket=vfDcA4sEUMs%3d&tabid=635&mid=1584 (accessed 30 May 2013).
- Mathew TH, Johnson DW, Jones GR. Chronic kidney disease and automatic reporting of estimated glomerular filtration rate: revised recommendations. Med J Aust 2007;187:459–63.[PubMed]