4364.0.55.005 - Australian Health Survey: Biomedical Results for Chronic Diseases, 2011-12  
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Contents >> Chronic kidney disease >> Kidney disease biomarkers





KIDNEY DISEASE BIOMARKERS

The National Health Measure Survey (NHMS) measured two aspects of kidney function: estimated glomerular filtration rate (eGFR) and the presence of albuminuria. eGFR uses a formula to estimate the amount of blood the kidneys filter per minute, which indicates if and to what extent kidney function is impaired. Albuminuria occurs when albumin (a protein) leaks into the urine from the blood through the kidneys.1 While abnormal levels on either test indicate the presence of some form of kidney damage, they alone cannot diagnose kidney disease.

    Data source and definitions

    The NHMS included two tests for kidney function: estimated glomerular filtration rate (eGFR) and the presence of albuminuria.

    eGFR
    • eGFR was measured via a blood test. Abnormal kidney function using eGFR is defined as a reading of less than 60 mL/min/1.73m.

    Albuminuria
    • Presence of albuminuria was measured via a urine test. The presence of albuminuria is defined as an albumin creatinine ratio (ACR) reading of greater than or equal to 2.5 mg/mmol for males and greater than or equal to 3.5 mg/mmol for females.


IMPAIRED ESTIMATED GLOMERULAR FILTRATION RATE (eGFR)

Estimated glomerular filtration rate measures the rate at which the kidneys filter wastes from the blood, and is considered to be the best measure of kidney function.2 Impaired eGFR levels indicate that the kidneys are not working properly.

In 2011–12, 3.6% or around 620,000 people aged 18 years and over had impaired eGFR, with no significant difference between men (3.3%) and women (3.9%). Rates of impaired eGFR were very low for people aged under 54 years (less than 1%) but then markedly increased to 29.6% of people aged 75 years and over.

Around one in ten adults (10.9%) with impaired eGFR self-reported that they had kidney disease as a current and long-term health condition.


Graph Image for Persons aged 18 years and over - Proportion with impaired estimated glomerular filtration rate (eGFR), 2011-12


High blood pressure is an important risk factor for chronic kidney disease as high blood pressure can damage the blood vessels supplying the kidneys.3 People who had high blood pressure in 2011–12 were more likely than those with normal blood pressure to have impaired eGFR (7.2% compared with 2.7%). The NHMS also showed that obesity, which is another risk factor for kidney disease, is also related to eGFR. In 2011-12, people who were obese had higher rates of impaired eGFR than those of normal weight or underweight (4.2% compared with 2.7%).

Impaired eGFR was associated with a number of other biomarkers of chronic disease. This was particularly the case for diabetes, which is a major cause of kidney disease. In 2011–12, 17.5% of people with impaired eGFR had diabetes compared with only 4.6% of those with normal eGFR. Kidney disease was also associated with anaemia, as kidney malfunction can reduce the number of red blood cells produced by the body.2 One in five (19.7%) people with impaired eGFR were at risk of anaemia in 2011–12 compared with 4.0% of those with normal eGFR.

Overall, 31.2% of those with impaired eGFR also had albuminuria.
PRESENCE OF ALBUMINURIA

Albuminuria is the presence of albumin (a type of protein) in the urine.3 Low levels of albumin in the urine are normal, but elevated levels may occur when kidney damage is present.1

In 2011–12, 1.3 million (or 7.7%) people aged 18 years and over had albuminuria, with higher rates for men than women (8.5% compared to 6.9%).

Like eGFR, the prevalence of albuminuria sharply increased from the age of 65 years, with people aged 75 years and over having the highest rates (22.5%).

Graph Image for Persons aged 18 years and over - Proportion with presence of albuminuria, 2011-12


The relationship between albuminuria and the other chronic disease biomarkers was similar to that for eGFR. For example, people who had albuminuria were more likely than those without albuminuria to have diabetes (15.1% compared with 4.0%), and to be at risk of anaemia (10.1% compared with 4.0%).

People who had high blood pressure were also more likely to have albuminuria than those who did not have high blood pressure (13.8% compared with 6.2%).

For more information on kidney disease biomarkers, see Tables 1, 2, 3, 6, 8, 9, and 15 on the Downloads page of this publication.

ENDNOTES

1 Department of Health, Victoria, Australia, Nov 2012, The Victorian Health Monitor, 2009-2010 <http://docs.health.vic.gov.au/docs/doc/CC6A20C055B5AA75CA257A80001A7128/$FILE/VHM%20report.pdf>, Last accessed 24/06/2013. Back to top
2 Kidney Health Australia, Jun 2013, Chronic Kidney Disease (CKD) Management in General Practice. 2nd Edition 2012 <http://www.kidney.org.au/HealthProfessionals/CKDManagementinGeneralPractice/tabid/789/Default.aspx>, Last accessed 24/06/2013. Back to top
3 Australian Institute of Health and Welfare, Jun 2013, An overview of Chronic Kidney Disease in Australia, 2009 <http://www.aihw.gov.au/WorkArea/DownloadAsset.aspx?id=6442459911>, Last accessed 24/06/2013. Back to top

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