CAUSES OF DEATH REVISIONS, 2016 REVISED DATA
This note was released on 26 March, 2019.

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 a preliminary 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 2016 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 52-60 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 specified 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 Up until the 2014 reference period, the ABS released the annual Causes of Death 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 six 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 preliminary coding of coroner-certified deaths needed to occur approximately six 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 With earlier release of preliminary data, there is now a period of 18 months between the release of preliminary and revised data. The table below shows the impact of this changed revisions process at the ICD-10 chapter level. As anticipated, the magnitude of changes is the largest for deaths assigned to the Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (Symptoms and signs) (R00-R99) chapter, decreasing by 20.8% in 2016. This is similar to the decrease in 2015 (26.9%), the first year the publication was released six months earlier. The redistribution of deaths to more specified ICD-10 codes is discussed in detail below.

Causes of death revisions for 2012 to 2016 - percentage change from preliminary to revised data, by selected ICD-10 chapter, all certified deaths (a)(b)(c)
	2012	2013	2014	2015	2016
Cause of death and ICD-10 code	%	%	%	%	%
Certain infectious and parasitic diseases (A00-B99)	0.0	0.2	0.1	0.4	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)	0.0	0.2	0.0	0.6	0.2
Endocrine, nutritional and metabolic diseases (E00-E90)	0.0	0.1	0.1	0.6	0.3
Mental and behavioural disorders (F00-F99)	0.0	0.0	0.0	0.1	0.0
Diseases of the nervous system (G00-G99)	0.2	0.1	0.1	0.4	0.1
Diseases of the circulatory system (I00-I99)	0.2	0.0	0.0	0.5	0.4
Diseases of the respiratory system (J00-J99)	0.0	0.0	0.1	0.4	0.3
Diseases of the digestive system (K00-K93)	0.1	-0.1	0.1	0.7	0.3
Diseases of the skin and subcutaneous tissue (L00-L99)	-0.3	0.0	0.2	0.2	0.2
Diseases of the musculoskeletal system and connective tissue (M00-M99)	-0.1	0.2	0.2	0.3	0.4
Diseases of the genitourinary system (N00-N99)	0.1	-0.1	0.0	0.3	0.1
Certain conditions originating in the perinatal period (P00-P96)	0.2	-0.5	0.0	0.4	0.5
Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)	0.4	0.2	0.5	1.0	0.7
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)	-10.1	-2.9	-5.6	-26.9	-20.8
External causes of morbidity and mortality (V01-Y98)	0.3	0.3	0.5	0.8	0.1

(a) Excludes deaths coded to H00-H59, H60-H95, and O00-O99 as these causes account for a small number of deaths and few are reassigned over the revisions process.
(b) Since 2015 the release of Causes of Death, Australia has occurred 6 months earlier, representing a significant change in processing of the national mortality dataset. For further information regarding changes to ABS coding processes, see A More Timely Annual Collection: Changes to ABS Processes (Technical Note) in Causes of Death, Australia, 2015 (cat. no. 3303.0).
(c) This table includes both doctor and coroner-certified deaths.

7 The table below provides the counts of deaths by ICD-10 chapter for the 2016 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 (R00-R99) chapter with corresponding increases in other chapters. 

8 Deaths which are originally coded to the Symptoms and signs (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 (76.5%), with Diseases of the circulatory system (I00-I99) being the most common natural cause. Of those reassigned to external causes of death, 16 were found to be suicides.

Causes of death revisions for 2016 - preliminary and revised data, by selected ICD-10 chapter, all certified deaths (a)(b)
	2016 reference year		Change (preliminary to revised)
	P	R
Cause of death and ICD-10 code	no	no	no	%
Certain infectious and parasitic diseases (A00-B99)	2,818	2,829	11	0.4
Neoplasms (C00-D48)	46,307	46,325	18	0.0
Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)	490	491	1	0.2
Endocrine, nutritional and metabolic diseases (E00-E90)	6,750	6,767	17	0.3
Mental and behavioural disorders (F00-F99)	9,931	9,935	4	0.0
Diseases of the nervous system (G00-G99)	8,794	8,805	11	0.1
Diseases of the circulatory system (I00-I99)	43,963	44,157	194	0.4
Diseases of the respiratory system (J00-J99)	14,783	14,822	39	0.3
Diseases of the digestive system (K00-K93)	5,753	5,773	20	0.3
Diseases of the skin and subcutaneous tissue (L00-L99)	532	533	1	0.2
Diseases of the musculoskeletal system and connective tissue (MOO-M99)	1,371	1,376	5	0.4
Diseases of the genitourinary system (N00-N99)	3,458	3,463	5	0.1
Certain conditions originating in the perinatal period (P00-P96)	550	553	3	0.5
Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)	587	591	4	0.7
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)	1,651	1,308	-343	-20.8
External causes of morbidity and mortality (V01-Y98)	10,736	10,746	10	0.1
Total(a)	158,504	158,504	na	na
na not applicable (a) Includes deaths coded to H00-H59, H60-H95, and O00-O99. (b) This table includes both doctor and coroner-certified deaths.

IMPACT OF REVISIONS - UNDERLYING CAUSE OF DEATH

9 The expected outcome of the revisions process is to improve data quality. Enhancements to underlying cause data quality may include improved understanding of either mechanism or intent or identifying an underlying cause where not previously possible. While the revisions process has a minimal impact at the chapter level (with the exception of Symptoms and signs (R00-R99)), data improvements become more apparent when considering movements within individual chapters.

10 The table below shows data for coroner-certified deaths only at the sub-chapter level. There were 139 coroner-certified deaths with an unspecified mechanism that were reassigned through the revisions process. The majority of these records had no change in intent, but were assigned a more specific mechanism. For example, a suicide death where the mechanism was unspecified at preliminary coding (Intentional self-harm by unspecified means (X84)) may be reassigned to a suicidal drowning (Intentional self-harm by drowning (X71)) during the revisions process when an autopsy becomes available for analysis.

11 The table below also shows that for deaths which were certified by a coroner, the number of cases assigned to Other ill-defined and unspecified causes of mortality (lll-defined causes of mortality) (R99) decreased by 34.5% from preliminary to revised output.


Causes of death revisions for 2016 - preliminary and revised, by selected causes of death, coroner-certified deaths (a)

		2016 reference year		Change (preliminary to revised)
		P	R
Cause of death and ICD-10 code		no	no	no	%
Other ill-defined and unspecified causes of mortality (R99)		1,006	659	-347	-34.5
Unspecified mechanism (X59, X84, Y09)		263	124	-139	-52.9
	Accidental exposure to unspecified factor (X59)	203	89	-114	-56.2
	Intentional self-harm by unspecified means (X84)	26	12	-14	-53.8
	Assault by unspecified means (Y09)	34	23	-11	-32.4
Event of undetermined intent (Y10-Y34)		140	122	-18	-12.9

(a) This table includes coroner-certified deaths only.

12 The table below provides information on changes at the sub-chapter level for the 2016 reference period, with a focus on the External causes of morbidity and mortality (V01-Y98) chapter.

Notable increases in deaths due to external causes include:

• Falls (W00-W19) increased by 53 deaths. For many of the deaths reassigned to a fall, the type of injury was known at preliminary coding (e.g. broken hip), yet the mechanism was unknown (e.g. the broken hip was caused by an unspecified accident). From preliminary to revised data, additional information about the nature of the mechanism became available allowing these records to be reassigned to a fall (e.g. the broken hip was identified to be due to a fall down stairs).

• Intentional self-harm (X60-X84, Y870) increased by 45 deaths. The majority of intentional self-harm deaths identified over the revisions process were originally assigned to deaths from an Accidental drug poisoning (X40-X44).

• Intentional drug poisoning (X60-X64) increased by 28 deaths. A large number of intentional drug poisoning deaths were identified due to updated intent information becoming available (especially the final coronial finding). Most Intentional drug poisonings (X60-X64) were reassigned from Accidental drug poisoning (X40-X44).

• Accidental drug poisoning (X40-X44) increased by 22 deaths. Many of the deaths reassigned to an accidental drug poisoning death were originally assigned to Ill-defined causes of mortality (R99). Drug-induced deaths require intensive investigations to accurately determine the cause and manner in which the death occurred. Over time, as investigations are finalised, more information on the NCIS becomes available allowing these deaths to be reassigned to accidental drug poisonings.

• Car occupant injured in transport accident (V40-V49) increased by 19 deaths. Many of these deaths were reassigned from Other land transport accidents (V80-V89), where information about the type of vehicle and passenger became known.

Causes of death revisions for 2016 - preliminary and revised, by ICD-10 selected causes, all certified deaths (a)(b)(c)

		2016 reference year		Change (preliminary to revised)
		P	R
Cause of death and ICD-10 code		no	no	no	%
Sudden infant death syndrome (R95)		26	34	8	30.8
Other ill-defined and unspecified causes of mortality (R99)		1,043	697	-346	-33.2
Transport accidents (V01-V99)		1,453	1,467	14	1.0
	Car occupant injured in transport accident (V40-V49)	751	770	19	2.5
	Other land transport accidents (V80-V89)	71	57	-14	-19.7
Other external causes of accidental injury (W00-X59)		5,705	5,684	-21	-0.4
	Falls (W00-W19)	2,666	2,719	53	2.0
	Accidental drug poisoning (X40-X44)	1,289	1,311	22	1.7
	Exposure to unspecified factor (X59) (a)	1,004	893	-111	-11.1
Intentional self-harm (X60-X84, Y870) (b)		2,866	2,911	45	1.6
	Intentional drug poisoning (X60-X64)	411	439	28	6.8
	Intentional self-harm by hanging or suffocation (X70)	1,583	1,590	7	0.4
	Intentional self-harm by drowning and submersion (X71)	62	70	8	12.9
	Intentional self-harm by unspecified means (X84)	26	12	-14	-53.8
Assault (X85-Y09)		244	254	10	4.1
Event of undetermined intent (Y10-Y34)		141	123	-18	-12.8

(a) Deaths assigned to Exposure to unspecified factor (X59) are more likely to be certified by a doctor. As such, % change shown in this table differs from the table presented above.
(b) Care should be taken in interpreting figures relating to intentional self-harm. See Explanatory Notes 91-100.
(c) This table includes both doctor and coroner-certified deaths. Figures presented in this table may show differences to the table above.

13 Various improvements to the national mortality system have been undertaken over several years. One major improvement undertaken by the NCIS is the more timely upload of reports and information for open coroner cases. This information can then be used at an earlier point by the ABS to improve open coding data quality. Specifically, earlier availability of reports can reduce the number of Ill-defined causes of mortality (R99) present in the dataset at preliminary coding. These improvements are now being reflected in the mortality dataset. A comparison of 2015 and 2016 preliminary Ill-defined causes of mortality (R99) counts indicate a substantial reduction, from 1,480 in 2015 to 1,043 in 2016.

14 There are some specific causes of death that may be more impacted by the changed revisions process. These include Accidental drug poisoning (X40-X44), Intentional drug poisoning (X60-X64) and Sudden Infant Death Syndrome (SIDS) (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. These deaths are particularly sensitive to the revisions process, in that more detailed information regarding the context of the death is often gained through revisions.

15 The number of deaths assigned to SIDS (R95) increased by 8 deaths between preliminary and revised coding. Of the 8 deaths that were reassigned to SIDS, 7 deaths were initially coded to Ill-defined causes of mortality (R99). While revised data captures a significant proportion of SIDS deaths, the rules for classifying these deaths are heavily influenced by specific terminology used in coronial findings. Data users should consider combining deaths coded to SIDS (R95) in conjunction with infant deaths coded to Ill-defined causes of mortality (R99) when seeking to understand how many sudden unexplained deaths in infants occur in total.

16 Over the revisions process there was an increase of 51 drug poisoning deaths (includes all intents: Accidental (X40-X44), Intentional (X60-X64) and Undetermined (Y10-Y14)). Intentional drug poisonings (X60-X64) contributed the largest increase across intent types for drug poisonings over the 2016 revisions process, accounting for 54.9% of the increase.

17 The process for determining that a death was caused by an Intentional drug poisoning (X60-X64) is complex, as multiple factors such as drug type, intent and presence of pre-existing natural disease need to be considered. Of the deaths reassigned to Intentional drug poisoning (X60-X64), approximately 38.8% were initially coded to Accidental drug poisoning (X40-X44). These deaths typically had only an initial police report available at preliminary coding, where details on the intent of death can be unclear. A further 22.4% of those reassigned to this category were initially coded to Ill-defined causes of mortality (R99). These deaths typically did not have toxicology and/or pathology reports available on NCIS at the time of preliminary coding.

18 Determining deaths from Accidental drug poisoning (X40-X44) is similarly complex. Around 49.2% of deaths reassigned to an Accidental drug poisoning (X40-X44) were coded at preliminary as Ill-defined causes of mortality (R99). A further 14.3% were coded to Undetermined drug poisoning (Y10-Y14) at preliminary.

IMPACT OF REVISIONS - ASSOCIATED CAUSES OF DEATH

19 The revisions process has traditionally focussed on improving specificity of the underlying cause of death. More recently, there has been growing interest in associated cause statistics which can provide a more complete picture of the diseases and/or circumstances that contributed to a death. Associated causes include the type of injuries sustained by a deceased person, drug type in a drug-induced death (e.g. heroin, cannabis), chronic disease (e.g. cancer) and mental and behavioural disorders (e.g. depression, anxiety). The ABS has maximised the use of improved report attachment on the NCIS to enhance associated cause statistics through the revisions process. Analysis of associated causes of death can better enable targeted policy and prevention initiatives, especially for those deaths which are deemed preventable. For this reason, the revisions process typically focusses on associated cause of death enhancements for two key areas - drug specification in drug-induced deaths and mental and behavioural disorders implicated in deaths from external causes.

Changes to drug types for drug-induced deaths

20 There are multiple complex factors which need to be considered when a death is certified as drug-induced. The timing between the death and toxicology testing can influence the levels and types of drugs detected, making it difficult to determine the true level of a drug at the time of death. Individual tolerance levels may also vary considerably depending on multiple factors, including sex, body mass and a person’s previous exposure to a drug. Consideration of contextual factors around the death must also be considered such as pre-existing natural disease and reports from friends and families regarding the circumstances surrounding death. For these reasons, the certification of a death as being drug-induced can take significant time to complete, making these deaths particularly sensitive to the revisions process.

21 Policies directed at reducing drug-induced deaths employ a variety of strategies depending on drug type. Information regarding the type of drug(s) in a drug-induced death can often depend on the availability of an autopsy, toxicology or coronial finding report. When these reports are not available, the drug type is unknown and coded to Other and unspecified drugs, medicaments and biological substances (Unspecified drug) (T509). Importantly, deaths coded with an Unspecified drug (T509) are still counted as a drug-induced death at preliminary output, but they may be enhanced with more specific information about drug type via the revisions process.

22 From preliminary to revised, the number of drug-induced deaths in 2016 where drug type was not specified (Unspecified drug (T509)) decreased from 110 to nine. As a result there was an increase in the number of specified drug types (see table below) with Benzodiazepines (T424) recording the largest increase (109 mentions) when analysed by single drug type. This was followed by Other and unspecified antipsychotics and neuroleptics (T435) (67 mentions) and Other and unspecified antidepressants (T432) (60 mentions).

Changes to associated cause drug types for 2016 - preliminary and revised, coroner-certified deaths (a)

	2016 reference year		Change (preliminary to revised)
	P	R
Cause of death and ICD-10 code	no	no	no	%
Benzodiazepines (T424)	662	771	109	16.5
Other and unspecified antipsychotics and neuroleptics (T435)	216	283	67	31.0
Other and unspecified antidepressants (T432)	276	336	60	21.7
Other opioids (T402)	550	603	53	9.6
Psychostimulants with abuse potential (T436)	362	414	52	14.4
Heroin (T401)	361	397	36	10.0
Cannabis (derivatives) (T407)	132	167	35	26.5
Methadone (T403)	208	240	32	15.4
4-Aminophenol derivatives (T391)	165	196	31	18.8
Other synthetic narcotics (T404)	234	263	29	12.4

(a) This table includes coroner-certified deaths only.

Changes to associated causes for intentional self-harm and accidental drug poisonings

23 Associated causes of death may provide important contextual information for deaths due to Intentional self-harm (X60-X84, Y870). At preliminary coding, 80.0% of suicides in 2016 had associated causes mentioned as contributory factors to death. Through revisions, this proportion increased to 86.5%. The table below shows the top five increases for associated causes of death as they relate to Intentional self-harm (X60-X84, Y870). Mood disorders (F30-F39), which include depression and bipolar affective disorder, were the most common associated causes of death identified during the revisions process, followed by Mental and behavioural disorders due to psychoactive substance use (F10-F19) and Suicide ideation (R458).


Changes to intentional self-harm associated causes for 2016 - preliminary and revised, coroner-certified deaths (a)

	2016 reference year		Change (preliminary to revised)
	P	R
Cause of death and ICD-10 code	no	no	no	%
Mood disorders (F30-F39)	1,135	1,318	183	16.1
Mental and behavioural disorders due to psychoactive substance use (F10-F19)	668	843	175	26.2
Suicide ideation (R458)	817	980	163	20.0
Anxiety and stress-related disorders (F40-F48)	327	447	120	36.7
Findings of alcohol, drugs and other substances in blood (R78)	459	529	70	15.3

(a) This table includes coroner-certified deaths only.

24 Associated causes may also provide critical insight into deaths due to Accidental drug poisoning (X40-X44). The table below shows the top five largest increases in associated causes for Accidental drug poisonings (X40-X44). As additional evidence and documentation was added to the NCIS there were 112 accidental drug overdoses where a Mental and behavioural disorders due to psychoactive substance use (F10-F19) such as addiction or chronic substance misuse was identified. Deaths in which Mood disorders (F30-F39) and Anxiety and stress-related disorders (F40-F48) were implicated increased by 50 and 39 respectively.

Changes to accidental drug poisoning associated causes for 2016 - preliminary and revised, coroner-certified deaths (a)
	2016 reference year		Change (preliminary to revised)
	P	R
Cause of death and ICD-10 code	no	no	no	%
Mental and behavioural disorders due to psychoactive substance use (F10-F19)	591	703	112	19.0
Mood disorders (F30-F39)	268	318	50	18.7
Anxiety and stress-related disorders (F40-F48)	136	175	39	28.7
Suicide ideation (R458)	52	80	28	53.8
Schizophrenia, schizotypal and delusional disorders (F20-F29)	85	100	15	17.6

(a) This table includes coroner-certified deaths only.