Assessing diabetes risk with AUSDRISK
Almost 900 000 Australians report living with diabetes1 and it is estimated that the actual prevalence of diabetes in the population is double this number with half the cases being undiagnosed.2 Diabetes contributes to 5% to the total disease burden in Australia3 and costs the economy around $1.3 billion every year.4
The burden of type 2 diabetes is increasing and is expected to be the leading cause of disease burden in Australia by 2023. Between 2003 and 2033 the prevalence is projected to increase by 221%. This increase is attributed to the expected growth in the prevalence of obesity.4
The impact of diabetes in Australia
- In 2007 around 7500 Australians died from diabetes and diabetes-related causes (5.4% of total deaths).5
- In 2003, 56% of people with diabetes had a disability and 40% of these had a severe limitation.5
- Nerve damage is a common complication that can lead to leg or foot amputations.6
- 60% of people with diabetes also have cardiovascular disease.5
- Adults with diabetes are more likely to have eye problems.6
- In 2005 one-third of people starting treatment for end-stage kidney disease had diabetic nephropathy.6
Why assess risk using AUSDRISK?
Progression to clinically relevant diabetes mellitus from impaired glucose tolerance can be prevented or delayed through lifestyle change and pharmaceutical interventions.7 Using glucose tolerance testing in every person suspected of being at high risk of diabetes is not practical7 and evidence suggests that around 40% of diabetes occurs people who returned a normal glucose tolerance test 3–5 years earlier.8
The AUSDRISK scoring system was developed to help predict incident diabetes based on demographic, lifestyle and anthropomorphic factors known to be associated with an increased risk of diabetes.7 Data were used from the Australian Diabetes, Obesity and Lifestyle study (AusDiab) and was validated in a population of 6060 participants aged over 25 years who did not have diabetes diagnosed at baseline.7
At a threshold of ≥ 12 the AUSDRISK score for identifying incident diabetes had:
- sensitivity: 74%
- specificity: 68%
- positive predictive value: 13%.7
The NHMRC, RACGP and Diabetes Australia recommend that people are assessed for diabetes risk using the AUSDRISK scoring system before requesting a fasting glucose test. A fasting glucose test should be performed in those found to have a score greater than 12. If the result is not definitive an oral glucose tolerance test is recommended.2,9,10
When and who to assess
The RACGP Red Book recommends assessing your patients using AUSDRISK for risk of developing diabetes every 3 years from age 40. Assess Aboriginal and Torres Strait Islander peoples from 18 years of age, as they are known to have increased risk for developing diabetes mellitus.
If your patient has any of the risk factors below, he/she is already considered to be at high risk and their fasting blood glucose should be tested every 3 years.
Risk factors for developing diabetes
- Previous cardiovascular event (MI or stroke).
- History of gestational diabetes.
- Polycystic ovary syndrome.
- Use of antipsychotic drugs.
What is involved in AUSDRISK calculation?
AUSDRISK is available in a number of mediums and on a variety of websites.
AUSDRISK is a scoring tool that assigns points for each risk factor. The final score is used to estimate the chance of developing incident diabetes in the next 5 years. People who return a score ≥ 12 are classified as high risk; the risk continues to increase with increasing scores. People who return a score greater than 20 have a 1 in 3 chance of developing diabetes.11
The following information is required to complete the AUSDRISK tool:
- age and sex
- ethnicity/country of birth
- family history of diabetes
- medical history of impaired glucose tolerance (including gestational)
- medically managed hypertension
- daily smoking
- consumption of fruit and vegetables
- physical activity level
- waist measurement.
Steps in assessing diabetes
The infographic below illustrates the steps in assessing diabetes.
- People from high risk groups or who are classified as high risk using AUSDRISK are given a blood glucose measurement.
- People with a fasting blood glucose (FBG) result of 5.5 to 6.9 mmol/L, or a random blood glucose (RBG) result of 5.5 to 11.0 mmol/L are then given an oral glucose tolerance test (OGTT).
- People with an OGTT result of 7.8 to 11.0 mmol/L have an impaired glucose tolerance and lifestyle interventions are recommended along with a retest in 12 months.
- People with an OGTT result if 11.1 or higher, an FBG result of 7.0 or higher, or an RBG result of 11.1 or higher, may be at high risk of diabetes. A repeat FBG to confirm the result is recommended. If the patient is asymptomatic, a retest in 12 months is also recommended.
- Australian Bureau of Statistics. Australian Health Survey: first results, 2011–12. 2012. www.abs.gov.au/ausstats (accessed 8 January 2013).
- Colagiuri R, Girgis S, Gomez M, et al. National evidence based guideline for the primary prevention of type 2 diabetes. Canberra: Diabetes Australia and the NHMRC, 2009.
- Begg S, Vos T, Barker B, et al. The burden of disease and injury in Australia 2003. Canberra: Australian Institute of Health and Welfare, 2007.
- Gross J. Projection of Australian health care expenditure by disease, 2003–2033. Canberra: Australian Institute of Health and Welfare 2008. www.aihw.gov.au/WorkArea/DownloadAsset.aspx?id=6442457498 (accessed 10 January 2013).
- Australian Institute of Health and Welfare. Diabetes impacts. 2012. www.aihw.gov.au/diabetes/impacts/#info (accessed 11 January 2012).
- Australian Institute of Health and Welfare. Diabetes: Australian facts 2008. Canberra: AIHW, 2008; Diabetes series no. 8. www.aihw.gov.au/publication-detail/?id=6442468075 (accessed 14 December 2012).
- Chen L, Magliano DJ, Balkau B, et al. AUSDRISK: an Australian type 2 diabetes risk assessment tool based on demographic, lifestyle and simple anthropometric measures. Med J Aust 2010;192:197–202. [PubMed]
- Unwin N, Shaw J, Zimmet P, et al. Impaired glucose tolerance and impaired fasting glycaemia: the current status on definition and intervention. Diabet Med 2002;19:708-23. www.ncbi.nlm.nih.gov/pubmed/12207806
- Diabetes Australia. Diabetes management in general practice. Diabetes Australia and The Royal College of General Practice, 2013. www.diabetesaustralia.com.au/Documents/DA/Publications/13.04.08%20DMiGP%20Web%20Version.pdf (accessed 2 April 2013).
- Guidelines for preventive activities in general practice (The Red Book) 8th Edition. Melbourne: The Royal Australian College of General Practitioners, 2012. www.racgp.org.au/your-practice/guidelines/redbook/ (accessed 8 January 2013).
- Department of Health and Ageing. The Australian type 2 diabetes risk assessment tool (AUSDRISK), 2010. www.health.gov.au/internet/main/publishing.nsf/Content/62703F3AFCA6268BCA25769400199781/$File/austool4.pdf (accessed 8 May 2013).