4363.0.55.001 - Australian Health Survey: Users' Guide, 2011-13  
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 11/12/2013   
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Contents >> Biomedical Measures >> Diabetes biomarkers

DIABETES BIOMARKERS

Diabetes is a chronic condition where insulin, a hormone that controls blood glucose levels, is no longer produced or not produced in sufficient amounts by the body.1 If left undiagnosed or poorly managed, diabetes can lead to coronary heart disease, stroke, kidney failure, limb amputations or blindness. In 2011, diabetes was the sixth leading cause of death in Australia.2

The National Health Measures Survey (NHMS) provides an objective measurement of the number of people with diabetes in Australia. It included two tests to measure diabetes: a fasting plasma glucose test and a glycated haemoglobin test (commonly referred to as HbA1c). Estimates of diabetes prevalence and management from the NHMS were derived using a combination of blood tests, medications use (see AHS referral form in the Downloads page of this product) and self reported information on diabetes from the National Health Survey (NHS) and the National Nutritional and Physical Activity Survey (NNPAS). The biomedical results from the NHMS can be used together with the self reported data to estimate disease prevalence rates. For details on self reported diabetes information, see the relevant Diabetes Mellitus chapter in this product.

DIABETES PREVALENCE

Diabetes prevalence was derived using a combination of blood test results and self-reported information on diabetes diagnosis and medication use.

A person was considered to have known diabetes if:

  • they had ever been told by a doctor or nurse that they have diabetes and they were taking diabetes medication (either insulin or tablets); OR
  • they had ever been told by a doctor or nurse that they have diabetes and their blood test result for fasting plasma glucose was greater than or equal to the cut off point for diabetes (that is, ≥7.0 mmol/L).
Note: people who had been told by a doctor or nurse that they have diabetes, but who were not taking medication for diabetes and did not have a fasting plasma glucose level ≥7.0 mmol/L, were classified as not having diabetes.

People with known diabetes were further classified as having Type I, Type II or Type unknown, based on the type of diabetes that a doctor or nurse told them they had. Women with gestational diabetes were excluded.
  • A person was considered to have newly diagnosed diabetes if they reported no prior diagnosis of diabetes but had a fasting plasma glucose value ≥7.0 mmol/L.
Total persons with diabetes was defined as the total number of persons with known diabetes and newly diagnosed diabetes.
  • A person was considered to be at high risk of diabetes if they did not currently have diabetes, but had an impaired fasting plasma glucose result, that is, a fasting plasma glucose level ranging from 6.1 mmol/L to less than 7.0 mmol/L.3

In the NHMS, the following definitions were used for fasting plasma glucose levels and glycated haemogloblin (HbA1c) levels:

Cut off points for Diabetes in the NHMS

Fasting plasma glucose (FPG)
(mmol/L)(a)
HbA1c (%)(b)

Has diabetes≥7.0≥6.5
At high risk of diabetes6.1 to <7.06.0 to <6.5
No diabetes<6.1<6.0

(a) Based on World Health Organization cut off points for fasting plasma glucose.3
(b) An HbA1c level of greater than or equal to 6.5% is the WHO recommended cut off point for diabetes.4

The NHMS diabetes classification outlined in Figure 1, illustrates how the combination of self reported diabetes data and diabetes test results has been used to define, known diabetes, newly diagnosed diabetes, persons at high risk of having diabetes and persons who do not have diabetes.

Figure 1: 2011–12 NHMS diabetes classification


* Cut off points for FPG: Indicates diabetes ≥7.0 mmol/L; At high risk of diabetes 6.1 to <7.0 mmol/L; Does not indicate diabetes <6.1 mmol/L.
Cut off points for HbA1c: Indicates diabetes ≥6.5%; At high risk of diabetes 6.0% to <6.5%; Does not indicate diabetes <6.0%.

DIABETES MANAGEMENT

In the National Health Measures Survey (NHMS), information on diabetes management is presented for those with known diabetes. See Figure 1 above for information on how this population is defined.

Goals for optimum diabetes management, as defined by the 2012–13 Diabetes Management in General Practice Guidelines5, are as follows:
  • Fasting blood glucose levels between 4.0–6.0 mmol/L
  • HbA1c levels less than or equal to 7.0%
  • Total cholesterol less than 4.0 mmol/L
  • HDL 'good' cholesterol greater than 1.0 mmol/L
  • LDL 'bad' cholesterol less than 2.0 mmol/L
  • Non-HDL-C cholesterol less than 2.5 mmol/L
  • Triglycerides less than 2.0 mmol/L
  • Albumin creatinine ratio (a kidney function test) less than 3.5 mg/mmol for women and less than 2.5 mg/mmol for men
  • Blood pressure less than or equal to 130/80 mmHg
  • 'Normal' Body Mass Index (i.e. a BMI score of between 18.0 and 24.9)
  • Non-smoker
  • Alcohol intake less than or equal to 2 standard drinks per day**
  • At least 30 minutes of physical activity 5 days per week**

**Note information on alcohol and physical activity targets have not been included in this release, as data for these variables are not available for all persons in the NHMS. However, this information can be sourced from the National Health Survey.

Comparability with other surveys

The NHMS is the first ABS survey to collect biomedical data on diabetes.

Diabetes biomedical data has been collected in other non-ABS surveys. However, caution must be taken when interpreting results due to the differences in scope, assay and the instrument used, and any thresholds applied in the final analysis. Further information about these comparisons is available from the Comparisons with other Australian surveys section of the Biomedical Results for Chronic Diseases, 2011-12 publication.

More information regarding the biomedical tests and cut off points can be found in the relevant subsections.

ENDNOTES

1 Diabetes Australia 2011, What is Diabetes?, <http://www.diabetesaustralia.com.au/en/Understanding-Diabetes/What-is-Diabetes/>, Last accessed 02/07/2013.
2 Australian Bureau of Statistics 2013, Causes of Death Australia, ABS cat. no. 3303.0, <http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/3303.0Chapter42011>, Last accessed 02/07/2013.
3 World Health Organization 2006, Definition and diagnosis of diabetes mellitus and intermediate hyperglycemia, <http://www.who.int/diabetes/publications/Definition%20and%20diagnosis%20of%20diabetes_new.pdf>, Last accessed 16/07/2013.
4 World Health Organization 2011, Use of Glycated Haemoglobin (HbA1c) in the Diagnosis of Diabetes Mellitus, <http://www.who.int/diabetes/publications/report-hba1c_2011.pdf>, Last accessed 16/07/2013.
5 Diabetes Australia 2012, Diabetes Management in General Practice. Guidelines for Type 2 Diabetes. <http://www.diabetesaustralia.com.au/Documents/DA/What's%20New/12.10.02%20Diabetes%20Management%20in%20General%20Practice.pdf>, Last accessed 20/06/2013.


This section contains the following subsection :
        Fasting plasma glucose
        Glycated haemoglobin (HbA1c)

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