Summary

Diabetes

Diabetes is a chronic condition marked by high levels of glucose (sugar) in the blood. It is caused by the inability to produce insulin (a hormone made by the pancreas to control blood glucose levels) or to use insulin effectively, or both.

The main types of diabetes are:

  • type 1 diabetes – a lifelong autoimmune disease that can be diagnosed at any age. The exact cause is unknown, but it is believed to be the result of an interaction of genetic and environmental factors
  • type 2 diabetes – a condition in which the body becomes resistant to the normal effects of insulin and gradually loses the capacity to produce enough insulin in the pancreas. The condition has strong genetic and family-related (non-modifiable) risk factors and is also often associated with modifiable risk factors. It is the most common form of diabetes
  • gestational diabetes – when higher than optimal blood glucose is present during pregnancy
  • other diabetes – a name for less common forms of diabetes resulting from a range of different health conditions or circumstances. This includes conditions affecting the pancreas and endocrine system, viral infections, genetic syndromes and in some cases, diabetes triggered from medications needed to manage or treat another health condition. Other diabetes may now also refer to new onset diabetes associated with COVID-19 infection and treatment for the virus (Sathish et al. 2021).

Treatment aims to maintain healthy blood glucose levels to prevent both short- and long-term complications, such as cardiovascular disease, kidney disease, blindness and lower limb amputation. Insulin replacement therapy is required by all people with type 1 diabetes, as well as by a proportion of people with other forms of diabetes if their condition worsens over time.

How common is diabetes?

In 2020, an estimated 1 in 20 (almost 1.3 million) Australians were living with diabetes (prevalence) and were registered with the National Diabetes Services Scheme (NDSS) and Australasian Paediatric Endocrine Group (APEG) state-based registers. This includes people with type 1 diabetes, type 2 diabetes and other diabetes, but excludes gestational diabetes.

In 2020, the prevalence of people with diabetes on the linked NDSS and APEG data increased with age. Almost 1 in 5 Australians aged 80–84 were living with diabetes in 2020 – this was almost 30 times as high as for those aged under 40 (0.7%). Diabetes was more common in males (4.8%) than females (3.8%), after controlling for age.

After accounting for differences in the age structure of the population, the age-standardised prevalence rate of diabetes on the linked NDSS and APEG data increased from 2.4% in 2000 to 4.3% in 2020. The diabetes rate peaked in 2016 and remained stable between 2016 and 2020 (Figure 1).

The prevalence rates presented above are likely to underestimate the true prevalence of diabetes in the Australian population. This is because they are based on people who have received a formal medical diagnosis of diabetes. However, Australian studies have shown that many people are living with undiagnosed type 2 diabetes. For example, in the 1999–2000 AusDiab Study, half of all diabetes was undiagnosed (Dunstan et al. 2001). In the 2011–12 Australian Bureau of Statistics (ABS) Australian Health Survey, which collected blood glucose data, 20% of participating adults aged 18 and over had undiagnosed diabetes prior to the survey (ABS 2013). In addition, registration with the NDSS is voluntary and people with type 2 diabetes are more likely to register if they access diabetes consumables to monitor their diabetes at home or require insulin. Despite these limitations, these data sources provide the best picture into the number of people living with diabetes in Australia to monitor changes in populations at risk and trends over time.

Further research is required to examine whether the proportion of people with undiagnosed type 2 diabetes in Australia has changed over time and the impact of this on the prevalence of disease in Australia.

Figure 1: Prevalence of diabetes from linked NDSS and APEG data, 2000 to 2020

This chart shows the estimated age–standardised proportion of people with diabetes based on data from the linked National Diabetes Services Scheme and Australasian Paediatric Endocrine Group between 2000 and 2020. The proportion increased from 2.4% in 2000 to 4.3% in 2020 but remained relatively stable between 2015 and 2020.

Type 1 diabetes

Around 55,400 people were newly diagnosed (incidence) with type 1 diabetes between 2000 and 2020 according to the National (insulin–treated) Diabetes Register (NDR).

In 2020, there were 3,100 people newly diagnosed with type 1 diabetes in Australia, equating to 12 diagnoses per 100,000 population.

The incidence of type 1 diabetes remained relatively stable across the last 2 decades, fluctuating between 11 and 13 new cases per 100,000 population.

Type 2 diabetes

Around 1.3 million people were newly diagnosed with type 2 diabetes between 2000 and 2020, according to linked NDSS and APEG data. This was around 60,000 people each year – an average of 166 new diagnoses a day.

There were 48,300 people newly diagnosed with type 2 diabetes registered on the linked NDSS and APEG data in Australia in 2020, equating to 188 diagnoses a day per 100,000 population.

According to the linked NDSS and APEG data, age-standardised incidence rates for type 2 diabetes have varied over time. Incidence rates peaked in 2008 at 336 per 100,000 population and have almost halved from 2008 to 2020 (172 per 100,000 population).

Gestational diabetes

In 2019–20, around 1 in every 7 (48,800) females aged 15–49 who gave birth in hospital were diagnosed with gestational diabetes, according to the National Hospital Morbidity Database.

Between 2000–01 and 2019–20, the age-standardised incidence of gestational diabetes in Australia more than tripled from 5.2% to 16.7% (Figure 2). However, caution should be taken when comparing rates over time. Several factors, including new diagnostic guidelines introduced across all states and territories between 2011 and 2013, are likely to have had an impact on the number of females diagnosed with gestational diabetes in recent years. Refer to Incidence of gestational diabetes in Australia—Changing trends for further information.

Figure 2: Incidence of gestational diabetes, 2000–01 to 2019–20

The chart shows that the proportion of females being diagnosed with gestational diabetes in Australia more than tripled according to the National Hospital Morbidity Database, from 5.2% in 2000–01 to 16.7% in 2019–20. Caution should be taken when comparing rates over time as a number of factors, including new diagnostic guidelines, are likely to have had an impact on the number of females diagnosed with gestational diabetes in recent years.

Impact of diabetes

Burden of disease

Burden of disease refers to the quantified impact of living with and dying prematurely from a disease or injury and is measured using disability-adjusted life years (DALY). One DALY is equivalent to one year of healthy life lost.

In 2018, type 2 diabetes was responsible for 112,500 DALY in Australia – equating to 4.5 per 1,000 population. Type 2 diabetes was the 12th leading contributor to total burden. After accounting for differences in the age structure of a population, the overall burden from type 2 diabetes decreased slightly from 3.9 per 1,000 population in 2003 to 3.8 per 1,000 population in 2018. Type 1 diabetes was responsible for 17,000 DALY, equating to 0.3 per 1,000 population – this was similar to the contribution in 2003 (0.4 per 1,000 population) (AIHW 2021a).

In 2018, 4.3% of the total burden of disease could have been prevented by reducing exposure to the modifiable risk factor ‘high blood plasma glucose levels’ (including diabetes) (AIHW 2021b).

See Burden of disease.

Expenditure

In 2018–19, an estimated $3.0 billion of expenditure in the Australian health system was attributed to diabetes, representing 2.3% of total disease expenditure. Of the $3.0 billion in expenditure:

  • type 2 diabetes represented 61%
  • type 1 diabetes 11%
  • gestational diabetes 2.0%
  • other diabetes 26% (AIHW 2021c).

See Health system expenditure.

Adverse effects in pregnancy

Based on data from the National Hospital Morbidity Database for 2019–20, mothers with pre-existing diabetes (and to a lesser extent, gestational diabetes) had higher rates of caesarean section, induced labour, pre-existing and gestational hypertension, and pre-eclampsia compared with mothers with no diabetes in pregnancy.

Babies of mothers living with diabetes in pregnancy are also at an increased risk of childhood metabolic syndrome, obesity, impaired glucose tolerance, and type 2 diabetes in later life (Clausen et al. 2007; Kim et al. 2012; Zhao et al. 2016).

See Pregnancy complications.

Deaths

According to the AIHW National Mortality Database, in 2020, diabetes was the underlying cause of around 5,100 deaths. However, it contributed to around 17,500 deaths (10.8% of all deaths) when associated causes are included. (AIHW 2021e).

See Deaths.

Treatment and management of diabetes

What is HbA1c?

Glycated haemoglobin, haemoglobin A1c or HbA1c, is the main biomarker used to assess long-term glucose control in people living with diabetes. Haemoglobin is a protein in red blood cells which can bind with sugar to form HbA1c. It is directly related to blood glucose levels and strongly related with the development of long-term diabetes complications. Because red blood cells can live for up to 120 days, HbA1c gives an indication of blood glucose over a few months.

HbA1c was endorsed for the diagnosis of diabetes in 2010 by the Australian Medical Association. Diagnosis is confirmed using HbA1c levels ≥48 mmol/L or ≥6.5%. HbA1c targets for people living with diabetes depend on the type of diabetes, life expectancy, risk of hypoglycaemia and other comorbidities.

HbA1c testing

According to the National Prescribing Service (NPS) MedicineInsight general practice insights report (NPS MedicineWise, 2021) in 2019–20, 67% of general practice patients with a diagnosis of diabetes (20 years and older) had at least one test result for HbA1c levels. Amongst MedicineInsight patients without a diagnosis of diabetes, only 11% had received at least one test for HbA1c levels.

According to the Australian National Diabetes Audit–Australian Quality Clinical Audit (ANDA–AQCA) 2021, amongst all adult patients with recorded diabetes (n=4,262), the median HbA1c level was 63.0 mmol/mol. Median HbA1c was slightly higher among patients with type 1 diabetes (66.0 mmol/mol) and slightly lower in patients with type 2 diabetes (62.0 mmol/mol). Patients with gestational diabetes had significantly lower median HbA1c levels (34.0 mmol/mol) (ANDA 2021).

See Ongoing monitoring.

Medicines

In 2020–21, there were over 16.5 million prescriptions dispensed for diabetes medicines through Section 85 of the Pharmaceutical Benefits Scheme and Repatriation Pharmaceutical Benefits Scheme, representing 5.3% of total prescriptions. Metformin, a glucose-lowering medication for patients with type 2 diabetes, was the seventh most dispensed medicine in 2020–21 (Department of Health 2021b).

According to the NDR, 30,800 people began using insulin to treat their diabetes in 2020. Of the people with diabetes who began using insulin, 52% had type 2 diabetes, 35% had gestational diabetes, 10% were newly diagnosed with type 1 diabetes and 2% had other forms of diabetes (AIHW 2022b).

See Medicines use.

Hospitalisations and procedures

Almost 1.2 million hospitalisations were associated with diabetes in 2019–20, with 5% recording diabetes as the principal diagnosis and 95% recording diabetes as an additional diagnosis, according to the AIHW National Hospital Morbidity Database. This represents 11% of all hospitalisations in Australia (AIHW 2021d).

Of the almost 1.2 million hospitalisations, just over 1 million recorded type 2 diabetes as the principal and/or additional diagnosis and 62,600 hospitalisations recorded type 1 diabetes as the principal and/or additional diagnosis.

People with diabetes may require procedures to manage their diabetes or treat the complications of diabetes. According to the National Hospital Morbidity Database, there were 3,500 weight loss procedures and 5,200 lower limb amputations undertaken for people with type 2 diabetes in 2019–20 (14 and 20 per 100,000 population, respectively).

See Hospitalisations.

Variation between population groups

The impact of diabetes varies between population groups. To account for differences in the age structures of these groups, the data presented below is based on age-standardised rates.

In recent years, the impact of diabetes has been higher among Aboriginal and Torres Strait Islander people, those living in lower socioeconomic areas and in remote areas (Figure 3). The diabetes prevalence rate was 2.9 times as high among Indigenous Australians as non–Indigenous Australians based on age–standardised self–reported data from the 2018–19 National Aboriginal and Torres Strait Islander Health Survey (ABS 2019b).

Generally, the impact of diabetes increases with increasing remoteness and socioeconomic disadvantage. Deaths related to diabetes were 1.9 times as high in Remote and very remote areas compared with Major cities, and 2.4 times as high in the lowest compared with the highest socioeconomic areas (Figure 3).

Figure 3: Impact of diabetes–variation between selected population groups

The table shows the age-standardised rate ratios for all diabetes by selected population groups. Rate ratios are presented for having diabetes (prevalence), hospitalised for diabetes, dying from diabetes and burden of disease. Overall, rates increased for each measure by increasing remoteness and socioeconomic disadvantage while rates were also higher among Indigenous people compared with non-Indigenous people.

Impact of COVID–19

The onset of the COVID–19 pandemic has significantly impacted the Australian health system, including mortality, hospitalisations, health services, disease management and surveillance. Diabetes is one of many conditions correlated with greater health consequences throughout the COVID-19 pandemic including increased risk of complication and mortality (Peric and Stulnig 2020).

Diabetes incidence

Some studies have proposed a link between COVID-19, hyperglycaemia and new onset diabetes (Sathish et al. 2021). In the 12 months between March 2020–2021 and March 2021–2022, the NDSS had 118,800 and over 119,000 new registrants, respectively. Both periods were higher than any previous 12 months recorded (Diabetes Australia 2022).

However, these new registrations may be due, at least in part, to people who were previously diagnosed with diabetes only registering with the NDSS during the pandemic. The increase in registrations may also be influenced by changes to the NDSS to simplify the usual processes to register (Andrikopoulos and Johnson 2020). Further monitoring is required to assess the influence on diabetes diagnoses during the COVID–19 pandemic.

Mortality

According to ABS COVID-19 Mortality data from January 2020 to March 2022, pre-existing chronic conditions such as diabetes were reported on death certificates for 3,600 (73%) of the 4,900 deaths due to COVID-19 (ABS 2022). Diabetes was a pre-existing condition in 20% of the 3,600 deaths.

COVID-19 hospitalisations

In 2020–21, there were over 4,700 hospitalisations in Australia that involved a COVID-19 diagnosis. Around 42% of hospitalisations with a diagnosis of COVID-19 had one or more diagnosed comorbid conditions, such as type 2 diabetes or cardiovascular disease, an increase from 25% in 2019–20. Of the 4,700 hospitalisations involving a COVID-19 diagnosis, the most common comorbid conditions associated with COVID-19 hospitalisations over this period were type 2 diabetes (20%) and cardiovascular disease (which includes coronary heart disease and a range of other heart, stroke and vascular diseases) (20%) (AIHW 2022c). 

Of those with a recorded comorbid diagnosis of type 2 diabetes:

  • 12% of hospitalisations involved time spent in an intensive care unit, compared with 7.0% of all COVID-19 hospitalisations.
  • 7.1% involved continuous ventilatory support, compared with 3.8% of all COVID-19 hospitalisations.
  • 19% had a separation mode indicating the patient died in hospital, compared with 10.3% of all COVID-19 hospitalisations.

Monitoring

According to NPS MedicineWise analysis of MedicineInsight, the rate of HbA1c testing over the 6-months from 1 March 2020 to 31 August 2020 fell significantly among regularly attending patients with a record of type 2 diabetes compared to all regularly attending patients. The rate of type 2 diabetes encounters remained similar in both time periods. In the pre-COVID period, the average monthly rate of HbA1c testing among patients with a record of type 2 diabetes was 126.1 per 1000 clinical encounters, which fell to 109.0 tests per 1,000 clinical encounters in the COVID period (NPS MedicineWise 2020).

In April 2020, there was a significant decline in the rate of HbA1c tests performed. The rate of testing for patients with a record of type 2 diabetes fell from 120 tests per 1,000 clinical encounters in April 2019 to 77 tests per 1,000 clinical encounters in April 2020 (NPS MedicineWise 2020).

With the COVID–19 pandemic continuing, it is still too early to predict the long-term impacts on diabetes and other chronic conditions.

See Impact of COVID–19.

Where do I go for more information?

For more information on diabetes, see:

Visit Diabetes for more on this topic.