3303.0 - Causes of Death, Australia, 2016  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 21/03/2018   
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CAUSES OF DEATH REVISIONS, 2015 REVISED DATA
This note was released on 21 March, 2018.

Overview
1 Deaths that are referred to a coroner can take time to be fully investigated. To account for this, the ABS has implemented a revisions process for those deaths where coronial investigations remained open at the time an initial cause of death was assigned. Data are deemed preliminary when first published, revised when published the following year and final when published after a second year. This technical note focusses specifically on revised data for 2015 coroner certified deaths.

2 The revisions process has been applied to all reference periods from 2006 onwards. Revisions are one of two measures implemented to enable timely data to be released on coroner-certified deaths (see Explanatory Notes 50-58 for further information). The second measure, referred to as 'open coding', ensures that all available documentation is taken into account when assigning a cause of death to coronial cases that are yet to be finalised. The combination of these two measures, along with ongoing enhancements in the timeliness and completeness of documentation on the National Coronial Information System (NCIS), have resulted in significant improvements to the quality of preliminary Causes of Death data. 

3 There are three main improvements to the Causes of Death data which are gained through the revisions process. Firstly, for deaths from natural causes a more specific condition may be identified. For example, a death may be coded to a condition such as cardiac arrest at preliminary coding, but with the later addition of an autopsy report, an underlying ischaemic heart condition could be identified. Secondly, for deaths from external causes (accidents, assaults and suicides) more information might be provided on mechanism. For example, a death coded to an unspecified accident with a fracture of hip, may later be found to have been caused by a fall down steps. Lastly, external causes may also have the intent of death updated through revisions. For example, a drug overdose where the intent of death was not determined at preliminary coding, may be updated to an intentional drug overdose when a coronial finding has been made. 

Changes to cause of death processing and revisions
4 Over the past 10 years, the ABS has released the annual Causes of Death, Australia dataset 15 months after the end of each reference period (i.e. data for the 2014 reference period was published in March 2016). The 2015 release of Causes of Death, Australia was released 6 months earlier, representing a significant change in processing of the national mortality dataset. 

5 Bringing forward the release of Causes of Death data meant that coding of coroner certified deaths needed to occur approximately 6 months earlier than in previous years. Given that the timeliness of report availability on the NCIS is critical to the ABS's ability to assign specific cause of death codes, considerable analysis was undertaken to ensure the preliminary dataset would be of sufficient quality to be fit for purpose. See Technical Note 1 - A More Timely Annual Collection: Changes to ABS Processes in the 2015 publication.

6 While the release of preliminary data occurred earlier, the release of revised data has been delayed with a period of 18 months elapsing between releases. Table 1 shows the impact of this changed revisions process at the ICD-10 chapter level. As anticipated, the magnitude of changes are greater, with deaths assigned to the Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified chapter (R00-R99) decreasing by 26.9%. The redistribution of deaths to more specified ICD-10 codes is discussed in more detail below.


TABLE 1 - CAUSES OF DEATH REVISIONS, by selected ICD-10 chapter - changes from preliminary to revised data: by percentage - 2011 to 2015

2011
2012
2013
2014
2015
Cause of death and ICD-10 code
%
%
%
%
%

Certain infectious and parasitic diseases (A00-B99)
0.0
0.0
0.2
0.1
0.4
Neoplasms (C00-D48)
0.0
0.0
0.0
0.0
0.0
Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism D50-D89
0.2
0.0
0.2
0.0
0.6
Endocrine, nutritional and metabolic diseases (E00-E90)
0.0
0.0
0.1
0.1
0.6
Mental and behavioural disorders (F00-F99)
0.2
0.0
0.0
0.0
0.1
Diseases of the nervous system (G00-G99)
0.0
0.2
0.1
0.1
0.4
Diseases of the circulatory system (I00-I99)
0.0
0.2
0.0
0.0
0.5
Diseases of the respiratory system (J00-J99)
-0.1
0.0
0.0
0.1
0.4
Diseases of the digestive system (K00-K93)
0.2
0.1
-0.1
0.1
0.7
Diseases of the skin and subcutaneous tissue (L00-L99)
0.5
-0.3
0.0
0.2
0.2
Diseases of the musculoskeletal system and connective tissue (MOO-M99)
0.2
-0.1
0.2
0.2
0.3
Diseases of the genitourinary system (N00-N99)
0.0
0.1
-0.1
0.0
0.3
Certain conditions originating in the perinatal period (P00-P96)
-0.3
0.2
-0.5
0.0
0.4
Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
0.7
0.4
0.2
0.5
1.0
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
-10.3
-10.1
-2.9
-5.6
-26.9
External causes of morbidity and mortality (V01-Y98)
0.8
0.3
0.3
0.5
0.8


Impact of revisions

7
The expected outcome of the revisions process is to improve data quality. Enhancements to data quality could include improved understanding of either mechanism or intent. It may also mean that an underlying cause is identified where that has not previously been possible. Table 2 focuses on changes in the number of deaths assigned to less specific codes, including Ill defined and unspecified causes (R99), those with an unspecified mechanism (X59, X84 and Y09) and those with an unspecified intent (Y10-Y34). Table 2 highlights that 47.3% of deaths with an unspecified mechanism were re-assigned through the revisions process, along with 28.0% of those with an unspecified intent.


TABLE 2: SELECTED CAUSES OF DEATH, DEATHS CERTIFIED BY A CORONER - Preliminary and Revised Data, Australia, 2015

2015 reference year
Change (prelim to revised)
P
R
Cause of death and ICD-10 code
no
no
no
%

R99
1 427
872
-555
-38.9
X59, X84, Y09
387
204
-183
-47.3
Y10-Y34
236
170
-66
-28.0


8 Table 3 provides the counts of deaths by ICD-10 chapter for the 2015 reference period from preliminary to revised. Revisions are most likely to result in decreases in the number of deaths assigned to the Symptoms and signs chapter (R00-R99) with corresponding increases in other chapters. 

9 Deaths which are originally coded to the Symptoms and signs chapter (R00-R99) chapter can be reassigned to specific natural or external causes of death. The majority of those reassigned are found to be deaths from natural causes (72.5%) with diseases of the circulatory system (I00-I99) being the most common natural causes assigned. Of those reassigned to external causes of death, only 15 were found to be suicide deaths.

TABLE 3 - CAUSES OF DEATH REVISIONS, (PRELIMINARY, REVISED) - by ICD-10 chapter - 2015 reference year

Preliminary
Revised
Change
Cause of death and ICD-10 code
no
no
no
%

Certain infectious and parasitic diseases (A00-B99)
2 843
2 855
12
0.4
Neoplasms (C00-D48)
46 551
46 574
23
0
Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)
522
525
3
0.6
Endocrine, nutritional and metabolic diseases (E00-E90)
6 638
6 677
39
0.6
Mental and behavioural disorders (F00-F99)
9 595
9 607
12
0.1
Diseases of the nervous system (G00-G99)
8 460
8 492
32
0.4
Diseases of the circulatory system (I00-I99)
45 392
45 605
213
0.5
Diseases of the respiratory system (J00-J99)
14 314
14 365
51
0.4
Diseases of the digestive system (K00-K93)
5 667
5 708
41
0.7
Diseases of the skin and subcutaneous tissue (L00-L99)
530
531
1
0.2
Diseases of the musculoskeletal system and connective tissue (MOO-M99)
1 302
1 306
4
0.3
Diseases of the genitourinary system (N00-N99)
3 535
3 544
9
0.3
Certain conditions originating in the perinatal period (P00-P96)
546
548
2
0.4
Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
581
587
6
1
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)
1 986
1 452
-534
-26.9
External causes of morbidity and mortality (V01-Y98)
10 573
10 659
86
0.8
Total(a)
159 052
159 052
0
0

(a) Includes deaths coded to H00-H59, H60-H95, and O00-O99.

10
While the revisions process has a minimal impact at the chapter level (with the exception of Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)), data improvements become more apparent when considering movements within individual chapters. Table 4 provides information on changes at the sub-chapter level for the 2015 reference period, with a focus on the External causes of morbidity and mortality (V01-Y98) chapter. Notable decreases include:
  • Other ill-defined and unspecified causes of mortality (R99) (-555 deaths);
  • Accidental exposure to other and unspecified factors (X58-X59) (-138 deaths); and
  • Event of undetermined intent (Y10-Y34) (-66 deaths);

Notable increases include:
  • Accidental poisoning by and exposure to noxious substances (X40-X49) (104 deaths);
  • Falls (W00-W19) (91 deaths);
  • Intentional self-harm (X60-X84) (38 deaths);
  • Car occupant injured in transport accident (V40-V49) (20 deaths); and
  • Sudden infant death syndrome (R95) (19 deaths).

TABLE 4: CAUSES OF DEATH REVISIONS (PRELIMINARY, REVISED), by ICD-10 selected causes - 2015

2015 reference year
Change (prelim to revised)
Preliminary
Revised
Cause of death and ICD-10 code
no
no
no
%

Sudden infant death syndrome (R95)
21
40
19
90.5
Other ill-defined and unspecified causes of mortality (R99)
1 427
872
-555
-38.9
Pedestrian injured in transport accident (V01-V09)
189
207
18
9.5
Pedal cyclist injured in transport accident (V10-V19)
37
39
2
5.4
Motorcycle rider injured in transport accident (V20-V29)
209
217
8
3.8
Car occupant injured in transport accident (V40-V49)
710
730
20
2.8
Occupant of pick-up truck or van injured in transport accident (V50-V59)
6
9
3
50.0
Occupant of heavy transport vehicle injured in transport accident (V60-V69)
33
34
1
3.0
Other land transport accidents (V80-V89)
107
87
-20
-18.7
Water transport accidents (V90-V94)
41
44
3
7.3
Air and space transport accidents (V95-V97)
33
35
2
6.1
Falls (W00-W19)
1 752
1 843
91
5.2
Exposure to inanimate mechanical forces (W20-W49)
93
102
9
9.7
Accidental drowning and submersion (W65-W74)
176
177
1
0.6
Other accidental threats to breathing (W75-W84)
87
92
5
5.7
Exposure to smoke, fire and flames (X00-X09)
54
50
-4
-7.4
Exposure to forces of nature (X30-X39)
29
32
3
10.3
Accidental poisoning by and exposure to noxious substances (X40-X49)
1 150
1 254
104
9.0
Accidental exposure to other and unspecified factors (X58-X59)
307
169
-138
-45.0
Intentional self-harm (X60-X84)(a)
3 027
3 065
38
1.3
Assault (X85-Y09)
265
274
9
3.4
Event of undetermined intent (Y10-Y34)
236
170
-66
-28.0
Drugs, medicaments and biological substances causing adverse effects in therapeutic use (Y40-Y59)
22
15
-7
-31.8
Surgical and other medical procedures as the cause of abnormal reaction of the patient, or of later complication, without mention of misadventure at the time of the procedure (Y83-Y84)
69
65
-4
-5.8
Sequelae of external causes of morbidity and mortality (Y85-Y89)
23
29
6
0.3

(a) Care should be taken in interpreting figures relating to intentional self-harm. See Explanatory Notes 88-96.


Summary of changes
11 The revision of Causes of Death data in 2015 saw a greater change between preliminary and revised counts when compared to previous years, particularly in the Signs and Symptoms (R00-R99) chapter. This change was anticipated as the 2015 reference period was the first time the Causes of Death dataset was published under the new release schedule. The majority of those deaths reassigned through the revisions process were found to be from natural causes, in particular Diseases of the Circulatory System (I00-I99). This demonstrates that there has been no significant impact on the quality or usability of the preliminary data as a result of the changed release schedule.

12 There are some specific causes of death that have been impacted more heavily by the changed revisions process. These include Accidental Drug Toxicity (X40-X44) and Sudden Infant Death Syndrome (R95). Deaths from these causes require intensive investigations to accurately determine the cause and manner in which the death occurred. Therefore some key reports may not be available on the NCIS when preliminary coding of these deaths occurs.

13 The number of deaths assigned to Sudden Infant Death Syndrome (R95) increased by 90.5% (19 Deaths) between preliminary and revised coding. All deaths that were reassigned to this ICD-10 code were initially coded to Other ill-defined and unspecified causes of mortality (R99). While revised data clearly captures a greater proportion of SIDS deaths, the rules for classifying these deaths are heavily influenced by specific wording used in coronial findings. Data users should consider combining deaths coded to Sudden Infant Death Syndrome (R95) in conjunction with infant deaths coded to Other ill-defined and unspecified causes of mortality (R99) when seeking to understand how many sudden unexplained deaths in infants occur in total.

14 The process for determining that a death was caused by an Accidental Drug Toxicity (X40-X44) is complicated as multiple factors such as drug type, intent and presence of natural disease need to be considered. Over half the deaths reassigned to an Accidental Drug Toxicity (X40-X44) (52.7%) were initially coded to Other ill-defined and unspecified causes of mortality (R99). These deaths were typically waiting on toxicology and pathology reports to be finalised at the time of preliminary coding. A further 27.9% of those reassigned to this category were initially coded to Intentional Drug Toxicity (X60-X64) or Drug Toxicity of Undetermined Intent (Y10-Y14). Data users should also note that multiple cause of death information such as drug type may not be available in preliminary data

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