DIABETES

Diabetes mellitus is a chronic metabolic condition where glucose levels are too high within the bloodstream. This is due to insulin, a hormone that controls blood glucose levels, no longer being produced or not being produced in sufficient amounts by the body (Diabetes Australia). According to the Australian Health Survey 2011-12, 4.6% of persons aged 2 years and over (999,000 people) had some type of diabetes (excluding persons with gestational diabetes). This included 0.6% of persons with Type 1 diabetes and 3.9% of persons with Type 2 diabetes.

Diabetes mellitus (E10-E14) was the sixth leading underlying cause of death of Australians in 2014, accounting for 4,348 or 2.8% of all deaths. The sex ratio for deaths due to diabetes was 104 male deaths per 100 female deaths.

Type 1 (E10) and Type 2 (E11) diabetes are the two main types of diabetes mellitus. Type 2 diabetes has links to both genetic and lifestyle factors, whereas Type 1 diabetes is not a lifestyle disease (Diabetes Australia). Over a ten-year time frame, Type 2 diabetes has increased by 36.7% as an underlying cause of death, rising from 1,482 deaths in 2005 to 2,026 in 2014. This is in contrast to Type 1 diabetes which showed a 6.5% decrease in the same period, declining from 338 deaths in 2005 to 316 deaths in 2014. Table 2.5 shows the breakdown of deaths due to Type 1 diabetes, Type 2 diabetes, and Diabetes mellitus in total over a ten-year time frame.

2.5 DIABETES DEATHS, Australia - Selected by Type - 2005-2014(a)(b)
	Type 1 Diabetes(c)	Type 2 Diabetes(d)	Total Diabetes(e)
2005	338	1 482	3 529
2006	344	1 519	3 669
2007	379	1 581	3 818
2008	384	1 849	4 181
2009	359	1 773	4 176
2010	345	1 653	3 948
2011	369	1 798	4 211
2012	372	1 794	4 241
2013	324	1 966	4 332
2014	316	2 026	4 348
(a) Causes of death data for 2014 are preliminary and subject to a revisions process. See Explanatory Notes 52-54 and the Causes of Death Revisions, 2012 and 2013 Technical Note in this publication.
(b) See Explanatory Notes 68-94 for further information on specific issues relating to time-series and 2014 data.

(c) Type 1 diabetes: E10 Insulin dependent diabetes mellitus.
(d) Type 2 diabetes: E11 Non-insulin dependent diabetes mellitus.
(e) Total diabetes: E10, E11; E12: Malnutrition related diabetes mellitus; E13: Other specified diabetes mellitus; E14: Unspecified diabetes mellitus.

In 2014, for all deaths assigned an underlying cause of Type 2 diabetes (E11), there were on average 5.5 conditions that appeared on the death certificate. This compares to an average of 3.3 conditions listed on all death certificates. Due to the high number of associated causes of death reported on a death certificate with an underlying cause of Type 2 diabetes, the multiple cause dataset offers greater insight into these deaths. Multiple causes include all conditions reported on the death certificate, whereas associated causes are all conditions on the death certificate other than the underlying cause of death.

Among deaths assigned an underlying cause of Type 2 diabetes, the most common associated causes were diseases of the circulatory system (I00-I99). In 2014, 47.9% of deaths due to Type 2 diabetes were reported with Ischaemic Heart Diseases (I20-I25) as an associated cause of death. The other diseases of the circulatory system most commonly listed with Type 2 diabetes included Hypertensive diseases (I10-I15) and Other forms of heart disease (I30-I52), which were present in 36.1% and 40.4% of all deaths due to Type 2 diabetes, respectively.

Importantly, Type 2 diabetes is more likely to be reported as an associated cause of death as opposed to an underlying cause of death. In these instances the certifier has recognised the diabetes as having a negative impact on the train of events leading to the person's death, but the diabetes did not initiate the train of morbid events. There has been a 45.2% increase in Type 2 diabetes as an associated cause of death over the 10 years from 2005 to 2014 (4,410 deaths in 2005 compared with 6,404 in 2014).

When Type 2 diabetes is reported as an associated cause of death, Ischaemic heart diseases (I20-I25) are the most frequent underlying cause of death in the WHO leading cause groupings. In 2014 there were 1,315 deaths due to Ischaemic heart diseases (I20-I25) with Type 2 diabetes reported as an associated cause of death. Dementia and Alzheimer's disease (F01, F03, G30) were the second highest underlying cause of death to have Type 2 diabetes reported as an associated cause, with 623 deaths reporting both conditions on the death certificate.

Other conditions likely to be an underlying cause of death with Type 2 diabetes reported as an associated cause are certain specified malignant neoplasms (C00-C97, D45). The three malignant neoplasms most likely to have Type 2 diabetes reported as an associated cause of death are Malignant neoplasm of bronchus and lung (C34), Malignant neoplasm of prostate (C61) and Malignant neoplasm of pancreas (C25), with 262, 151 and 144 deaths, respectively.

Type 2 diabetes also appears frequently with kidney disease and other complications of the renal system. Rather than appearing as an associated cause, the renal complications are linked to the diabetes code as a fourth character and output as an underlying cause of death with the code E112 Non-insulin dependent diabetes mellitus with renal complications. In 2014, 618 deaths were due to E112, meaning that 30.5% of deaths due to Type 2 diabetes were reported with renal complications.