Older age, First Nations/Pasifika/East Asian ethnic background, family history of diabetes, history of gestational diabetes mellitus, polycystic ovary syndrome, overweight/obesity, greater waist circumference, unhealthy diet, sedentary behaviour, poor sleep, smoking, metabolic syndrome, and medications that can induce hyperglycaemia.
Use of the Australian Type 2 Diabetes Risk Assessment Tool (AUSDRISK) can estimate progression to type 2 diabetes over 5 years, and is a formal screening tool.
In Australia, prediabetes is defined by one or more of:
There are three main blood tests used to diagnose prediabetes (and diabetes): glycated haemoglobin, a two hour 75g oral glucose tolerance test, or fasting blood glucose level.
Fasting blood glucose level (fBGL) involves taking blood glucose level after your patient has not had anything to eat or drink for at least eight hours. This shows how well the body is able to modulate blood sugar in a fasted state.
Two hour oral 75 g glucose tolerance test (75 g OGTT) is now rarely used in Australia for diagnosis of hyperglycaemia, except in pregnant women. You can explain that involves taking 75 grams of glucose as a sugary drink. Blood glucose levels are measured at baseline and two hours to determine how well the body’s insulin has processed the sugar.
Glycated haemoglobin, more commonly known as HbA1c, provides the longest term measure of blood sugar levels. You can explain to patients that it measures the amount of sugar bound to your red blood cells - cells that live for around three months. By testing HbA1c, you can diagnose prediabetes and diabetes, but also work out how well sugars have been under control over the past three months.
General population >40 years:
Use the AUSDRISK every 3 years or opportunistically to reassess risk.
Aboriginal and Torres Strait Islander people >18 years:
Test fBGL or HbA1c annually to screen, with OGTT for equivocal results.
High risk population >18 years (higher risk groups as above, or AUSDRISK ≥12):
Test fBGL or HbA1c annually to screen, with OGTT for equivocal results.
Recheck fBGL or HbA1c annually; use OGTT in individuals with IGT.
Every three to twelve months, depending on the degree of hyperglycaemia and test used. Refer to specialist as required.
Prediabetes confers an independently increased risk of cardiovascular events such as heart attack and stroke. Many of the risk factors for diabetes are also risk factors for cardiovascular disease.
When screening with the AUSDRISK, consider also applying the Australian Heart Association CVD Risk Calculator.
*Flip each card to reveal the correct answer.
One in two
One in six
One in ten
One in one hundred
One in six
White bread
Raspberries
Potatoes
Ice cream
Raspberries
Fasting blood glucose of 6.1-6.9 mmol/L
2-hour blood glucose after 75 g glucose of 7.8-11.1 mmol/L
Random blood glucose of 6.1-6.9 mmol/L
HbA1c of 6.0-6.4%
Random blood glucose of 6.1-6.9 mmol/L
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The Prediabetes website is an educational website developed by diabetes clinicians and academics. It is not intended as a substitute for formal medical advice. We recommend you seek care from your normal general practitioner or healthcare provider for diagnosis and management of prediabetes.
The DO-CAG recognises and pays respect to the Elders and communities – past, present, and emerging – of the lands on which we work and live. For thousands of years, they have shared and exchanged knowledges across innumerable generations for the benefit of all.