3303.0 - Causes of Death, Australia, 2008 Quality Declaration
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 31/03/2010
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3 The registration of deaths is the responsibility of the eight individual state and territory Registrars of Births, Deaths and Marriages. As part of the registration process, information about the cause of death is supplied by the medical practitioner certifying the death or by a coroner. Other information about the deceased is supplied by a relative or other person acquainted with the deceased, or by an official of the institution where the death occurred. The information is provided to the Australian Bureau of Statistics (ABS) by individual Registrars for coding and compilation into aggregate statistics. In addition, the ABS supplements this data with information from the National Coroners Information System (NCIS). The following diagram shows the process undertaken in producing cause of death statistics for Australia.
4 Note that prior to 2007, statistics on perinatal deaths were included in this publication. From 2007 onward, perinatal deaths data have been published separately in Perinatal Deaths, Australia (cat.no. 3304.0).
5 Statistics on Suicide deaths for years prior to 2006 were published separately in Suicides, Australia (cat. no. 3309.0).
6 The data presented in this publication are also included in a series of data cubes that are available on the ABS website.
7 A Glossary is also provided which details definitions of terminology used.
8 These Explanatory Notes provide salient details relevant to the Causes of Death collection.
2008 SCOPE AND COVERAGE
9 The statistics in chapters 1-7 relate to the number of deaths registered, not those which actually occurred, in the years shown. Number of deaths by year of occurrence will be published separately in mid 2010.
Scope of causes of death statistics
10 The ABS causes of death collection includes all deaths that occurred and were registered in Australia, including deaths of persons whose usual residence is overseas. Deaths of Australian residents that occurred outside Australia may be registered by individual Registrars, but are not included in ABS deaths or causes of death statistics.
11 The current scope of the statistics includes:
12 The scope of the statistics excludes:
13 From the 2007 reference year, the scope (time period) of the collection is:
14 Note that up to and including the 2006 issue of Causes of Death, Australia (cat. no. 3303.0), the scope (time period) for each reference year included:
Coverage of Causes of Death Statistics
15 Ideally, for compiling annual time series, the number of events (deaths) should be recorded and reported as those occurring within a given reference period such as a calendar year. However, due to lags in registration of events and subsequent delays in the provision of that information to the ABS, not all deaths are registered in the year that they occur. This ideal is unlikely to be met under the current legislation and registration processes. Therefore, the occurrence event is approximated by addition of the event on a state/territory register of deaths. Also, some additions to the register can be delayed in being received by the ABS from the Registrar (processing or data transfer lags).
In effect there are 3 dates attributable to each death registration:
16 Approximately 4% to 6% of deaths occurring in one year are not registered until the following year or later. These are included with the count of registered deaths published for that year.
17 A range of socio-demographic data are available from the causes of death collection. Standard classifications used in the presentation of causes of death statistics include age, sex, birthplace, marital status, multiple birth and Indigenous status. Statistical standards for social and demographic variables have been developed by the ABS. Where these are not published in the Causes of Death publication or data cubes, they can be sourced on request from the ABS.
18 Within ABS causes of death statistics, marital status relates to registered marital status. Registered marital states refers to formally registered marriages or divorces for which the partners hold a certificate.
19 For further information about marital status refer to Family, Household and Income Unit Variables, 2005 (cat. no. 1286.0)
20 The term Indigenous is used to refer to Aboriginal and Torres Strait Islander Australians. Those who are identified as being of Aboriginal and/or Torres Strait Islander origin through the death registration process are classified as Indigenous persons.
21 For further information about Indigenous status refer to Standards for Statistics on Cultural and Language Diversity, 1999 (cat. no. 1289.0)
22 The occupation classification used in ABS causes of death statistics is the Australian and New Zealand Standard Classification of Occupations (ANZSCO) First Edition 2006. However, the ABS has not published causes of death data with an occupation variable since the 2002 reference year. The ABS considers the quality of the data able to be produced for this variable to be insufficient for reasonable analysis.
23 For further information on ANZSCO First Edition, refer to ANZSCO: Australian and New Zealand Standard Classification of Occupation, First Edition (cat. no. 1220.0).
Australian Standard Geographical Classification (ASGC)
24 The ASGC is an hierarchical classification system consisting of six interrelated classification structures. The ASGC provides a common framework of statistical geography and thereby enables the production of statistics which are comparable and can be spatially integrated. Causes of death statistics are coded to Statistical Local Area (SLA) and can be produced for aggregates of these, for example, Statistical Division, Statistical Sub-Division and State.
25 For further information about the ASGC refer to Australian Standard Geographical Classification (ASGC), Jul 2009 (cat. no. 1216.0).
Standard Australian Classification of Countries (SACC)
26 The SACC groups neighbouring countries into progressively broader geographic areas on the basis of their similarity in terms of social, cultural, economic and political characteristics. Causes of death statistics are coded using the SACC, as the collection includes overseas residents whose death occurred while they were in Australia.
27 Birthplaces within Australia are coded to the state/territory level where possible. The supplementary codes contain the relevant state and territory 4-digit codes.
28 For further information about the classification, refer to Standard Australian Classification of Countries (SACC), (Second Edition) (cat. no. 1269.0).
International Classification of Diseases (ICD)
29 The International Classification of Diseases (ICD) is the international standard classification for epidemiological purposes and is designed to promote international comparability in the collection, processing, classification, and presentation of causes of death statistics. The classification is used to classify diseases and causes of disease or injury as recorded on many types of medical records as well as death records. The ICD has been revised periodically to incorporate changes in the medical field. Currently ICD 10th revision is used for Australian causes of death statistics.
30 ICD-10 is a variable-axis classification meaning that the classification does not group diseases only based on anatomical sites, but also on the type of disease. Epidemiological data and statistical data is grouped according to:
31 For example, a systemic disease such as septicaemia is grouped with infectious diseases; a disease primarily affecting one body system, such as a myocardial infarction is grouped with circulatory diseases; and a congenital condition such as spina bifida is grouped with congenital conditions.
32 For further information about the ICD refer to WHO International Classification of Diseases (ICD).
33 The ICD 10th Revision is also available online.
2008 MORTALITY CODING
34 The extensive nature of the ICD enables classification of causes of death at various levels of detail. For the purpose of this publication, data is presented according to the ICD at the chapter level, with further disaggregation for major causes of death.
35 To enable the reader to see the relationship between the various summary classifications used in this publication, all tables show in brackets the ICD codes which constitute the causes of death covered.
Updates to ICD-10
36 The Updating and Revision Committee (URC), a WHO advisory group on updates to ICD-10, maintains the cumulative and annual lists of approved updates to the ICD-10 classification. The updates to ICD-10 are of numerous types including addition and deletion of codes, changes to coding instructions and modification and clarification of terms.
37 The cumulative list of ICD-10 updates can be found online.
38 The ABS implemented a new version of the automated cause of death coding software (Medical Mortality Data System (MMDS)) for 2006 data onwards. The MMDS coding software incorporates coding algorithms to ensure that updates to ICD-10 are implemented in the production of the statistics.
External Causes of Death
39 Where an accidental or violent death occurs, the underlying cause is classified according to the circumstances of the fatal injury, rather than the nature of the injury, which is coded separately.
Leading Causes of Death
40 Ranking causes of death is a useful method of describing patterns of mortality in a population and allows comparison over time and between populations. However, different methods of grouping causes of death can result in a vastly different list of leading causes for any given population. A ranking of leading causes of death based on broad cause groupings such as 'cancers' or 'heart disease' does not identify the leading causes within these groups, which is needed to inform policy on interventions and health advocacy. Similarly, a ranking based on very narrow cause groupings or including diseases that have a low frequency, can be meaningless in informing policy.
41 Tabulations of leading causes presented in this publication are based on research presented in the Bulletin of the World Health Organisation, Volume 84, Number 4, April 2006, 257-336 . The determination of groupings in this list is primarily driven by data from individual countries representing different regions of the world. Other groupings are based on prevention strategies, or to maintain homogeneity within the groups of cause categories.
42 A number of organisations publish lists of leading causes of death, however the basis for determining the leading causes may vary. For example, many lists are based on Years of Potential Life Lost (YPLL) and are designed to present data based on the burden of mortality and disease to the community. The basis of the ABS listing of leading causes is based on the numbers of deaths and is designed to present information on incidence of mortality rather than burden of mortality.
Years of Potential Life Lost (YPLL)
43 Years of Potential Life Lost (YPLL) measures the extent of 'premature' mortality, which is assumed to be any death at ages of 1-78 years inclusive, and aids in assessing the significance of specific diseases or trauma as a cause of premature death.
44 Estimates of YPLL are calculated for deaths of persons aged 1-78 years based on the assumption that deaths occurring at these ages are untimely. The inclusion of deaths under one year would bias the YPLL calculation because of the relatively high mortality rate for that age, and 79 years was the median age at death when this series of YPLL was calculated using 2001 as the standard year. As shown below, the calculation uses the current ABS standard population of all persons in the Australian population at 30 June 2001. This standard is revised every 10 years.
45 YPLL is derived from:where: = adjusted age at death. As age at death is only available in completed years the midpoint of the reported age is chosen (e.g. age at death 34 years was adjusted to 34.5). = registered number of deaths at age due to a particular cause of death.
YPLL is standardised for age using the following formula: where the age correction factor is defined for age as: where: = estimated number of persons resident in Australia aged 1-78 years at 30 June 2008 = estimated number of persons resident in Australia aged years at 30 June 2008 = estimated number of persons resident in Australia aged years at 30 June 2001 (standard population)= estimated number of persons resident in Australia aged 1-78 years at 30 June 2001 (standard population)
State and Territory Data
46 Causes of death statistics for states and territories in this publication have been compiled in respect of the state or territory of usual residence of the deceased, regardless of where in Australia the death occurred and was registered. Deaths of overseas usual residents which occur in Australia are included in the state/territory in which their death was registered.
47 Statistics compiled on a state or territory of registration basis are available on request.
2008 DATA QUALITY
Coroner Certified Deaths
48 In compiling causes of death statistics, the ABS employs a variety of measures to improve quality, which include:
49 The quality of causes of death coding can be affected by changes in the way information is reported by certifiers, by lags in completion of coroner cases and the processing of the findings. While changes in reporting and lags in coronial processes can affect coding of all causes of death, those coded to Chapter XVIII: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified and Chapter XX: External causes of morbidity and mortality are more likely to be affected because the code assigned within the chapter may vary depending on the coroner's findings.
50 Over time, there have been variances in the way that the ABS has approached the coding of coroner certified cases. These variances have served to improve the quality of causes of death data over this time, but have not been significant enough to cause a break-in-series to the collection. The processing changes which have occurred over time are (processing year):
51 Further information on issues regarding changes to processing which has impacted the 2008 data can be found in Technical Note 1: 2008 COD Collection - Process Improvements.
52 Further information on the causes of death revision process and how it has been undertaken can be found in Technical Note 2: Causes of Death - Revisions Process.
53 This publication includes the number of registered Indigenous deaths for 2008. However, because of the data quality issues outlined below, more detailed breakdowns of Indigenous deaths are provided only for New South Wales, Queensland, South Australia, Western Australia and the Northern Territory.
54 There are several data collection forms on which people are asked to state whether they are of Indigenous origin. Due to a number of factors, the results are not always consistent. The likelihood that an indigenous person will identify, or be identified, as Indigenous on a specific form is known as their propensity to identify as Indigenous. Propensity to identify as Indigenous on a specific form can be thought of as a proportion of the total, unknown, number of Indigenous people who identify as such.
55 Propensity to identify as Indigenous is determined by a range of factors, including: how the information is collected; who completes the form; the perception of how the information will be used; education programs about identifying as Indigenous; and cultural issues associated with identifying as Indigenous.
56 While it is considered likely that most deaths of Indigenous Australians are registered, a proportion of these deaths are not identified as Indigenous by the family, health worker or funeral director during the death registration process. That is, whilst data is provided to the ABS for the Indigenous status question for 99% of all deaths, there are concerns regarding the accuracy of the data. For example, the Indigenous status question is not always asked of relatives and friends of the deceased by the funeral director.
57 In addition to those deaths identified as Indigenous, a number of deaths occur each year where Indigenous status is not stated on the death registration form. In 2008 there were 1,807 deaths registered in Australia for which Indigenous status was not stated, representing 1.3% of all deaths registered. The Australian Capital Territory, Queensland and Victoria had the highest proportions of not stated responses in 2008.
58 As a proportion of all deaths registered, deaths for which Indigenous status was not stated increased from 1.0% in 2007 to 1.3% in 2008. This was largely due to an increase in the number of deaths in New South Wales for which Indigenous status was not stated; from 212 in 2007 to 504 in 2008. Victoria also recorded an increase in deaths where Indigenous status was not stated, from 437 in 2007 to 553 in 2008.
59 From 2007, Indigenous status recorded for deaths registered in South Australia, Western Australia, Tasmania, the Northern Territory and the Australian Capital Territory has been sourced from both the Death Registration Form (DRF) and the Medical Certificate of Cause of Death (MCCD). Prior to 2007, Indigenous status was sourced only from the DRF. This method of using both forms to determine Indigenous status resulted in an additional 44 deaths recorded as Indigenous in 2008, representing a 0.7% increase in the number of deaths recorded as Indigenous for Australia overall. In addition, a further 1,652 records were reclassified from 'not stated' Indigenous status to 'non-Indigenous'.
60 Despite the relatively low number of deaths with Indigenous status not stated, it is likely that some Indigenous deaths are included in the not stated category, contributing to the under-coverage of Indigenous deaths.
61 Quality studies conducted as part of the Census Data Enhancement project have investigated the levels and consistency of Indigenous identification between the 2006 Census and death registrations. See Information Paper: Census Data Enhancement - Indigenous Mortality Quality Study, 2006-07 (cat. no. 4723.0), released on 17 November 2008.
62 An assessment of various methods for adjusting incomplete Indigenous death registration data for use in compiling Indigenous life tables and life expectancy estimates is presented in Discussion Paper: Assessment of Methods for Developing Life Tables for Aboriginal and Torres Strait Islander Australians, 2006 (cat. no. 3302.0.55.002), released on 17 November 2008.
SPECIFIC ISSUES FOR 2008 DATA
63 A number of issues should be taken into account by users when analysing the 2008 causes of death data, as outlined below.
Infectious and parasitic diseases (A00-B99)
64 Deaths coded to Sequelae of other and unspecified infections and parasitic diseases (B94) increased by 51 from 148 in 2007 preliminary to 199 in 2008, while deaths coded to Chronic viral hepatitis (B18) decreased by 56 from 92 in 2007 preliminary to 36 in 2008. The ABS increased resources in investigating and reviewing all records for the categories Acute hepatitis B (B16), Other acute viral hepatitis (B17) and Chronic viral hepatitis (B18). Where the record indicated a duration of 1 year or more, or led to another chronic condition, these codes were changed to Sequelae of viral hepatitis (B942).
65 Since 2006, there has been a significant increase in the number of deaths coded to Dementia (F01-F03). Updates to the coding instructions in ICD-10 has resulted in the assignment of some deaths shifting from Cerebrovascular diseases (I60-I69) to Vascular dementia (F01). In addition, changes to the Veterans’ Entitlements Act 1986 and Military Rehabilitation and Compensation Act 2004, and a subsequent promotional campaign targeted at health professionals, now allow for death from vascular dementia of veterans or members of the defence forces to be related to relevant service.
Diseases of the circulatory system (I00-I99)
66 Due to increased resources in investigating and reviewing records with a change of codes to Sequelae when the duration is over 12 months, the underlying cause of Sequelae of cerebrovascular disease (I69) increased by 302 (13%) from 2,398 in 2007 (prior to revisions process) to 2,700 in 2008.
Unspecified Causes of Mortality
67 During processing of causes of death data for 2008, the ABS increased effort in coding and analysing Medical Certificate of Cause of Death and quality assurance. More time was taken to investigate part 2 of the certificate when a non-specific underlying cause was shown in part 1. Part 2 of the certificate details conditions that may have contributed to the death but were not part of the sequence of events that led to death. The ABS also increased resources and time spent investigating coroners reports to identify specific causes of death. This process involved making increased use of police reports, toxicology reports, autopsy reports and coroners findings to minimise the use of non-specific causes and intents.
68 These changes have resulted in a decrease of 381 (33%) in the number of coroner certified deaths attributed to Other ill-defined and unspecified causes of mortality (R99) from 1,160 in 2007 preliminary to 779 in 2008 preliminary. Further information on the process changes and the impact they have had on 2008 data can be found in Technical Note 1: 2008 COD Collection - Process Improvements.
Transport Accidents (V01-V99, Y85)
69 The Department of Infrastructure, Transport, Regional Development and Local Government has published data in Road Deaths Australia 2008, Statistical Summary on the number of deaths due to road traffic accidents in 2008 (1,464 deaths). 2008 causes of death data recorded 1,253 deaths due to road traffic accidents (V01-V79) and a further 145 deaths were coded as Crashing of a motor vehicle, undetermined intent (Y32). The remaining difference in the numbers (66 deaths) between the two collections are explained by the different scope and coverage rules for each collection. In addition, a number of road traffic related deaths may be coded to Other ill-defined and unspecified causes of mortality (R99) due to the unavailability of information on the NCIS. It is important to note that the number of deaths attributed to transport accidents for 2008 will change as data is subject to the revisions process. See Technical Note 2: Causes of Death - Revisions Process for further information.
Assault (X85-Y09, Y87.1)
70 The number of deaths recorded as Assault (X85-Y09, Y87.1) ie murder and manslaughter and their sequelae, published in the Causes of Death publication vary from those published by the ABS in Recorded Crime - Victims, Australia, 2008 (cat. no. 4510.0). Differences in the scope and coverage of the two collections and pending finalisation of legal proceedings may account for the difference between the figures. It is important to note that the number of deaths attributed to assault for 2008 is expected to increase as data is subject to the revisions process. See Technical Note 2: Causes of Death Revisions Process for further information.
71 The following codes may include cases which could potentially have been assaults but for which the intent was determined to be other than Assault. Such cases cannot be separately identified in the final causes of death statistics:
Intentional Self-Harm [Suicide] (X60-X84, Y87.0)
72 The number of deaths recorded as Intentional self-harm (Suicide) has decreased over the last 10 years, from 2,492 in 1999 to 2,191 in 2008. This decrease can be partly attributed to the variances in the way the ABS has coded coroner certified deaths over time. See Explanatory notes 48-52. For 2008, the ABS has invested additional effort into coding coroner cases which remained open at the time of processing. This process involved making increased use of police reports, toxicology reports, autopsy reports and coroners findings to assign a more specific cause of death. This will have an influence on the number of deaths due to Suicide, as the majority of open coroner cases are deaths due to external causes. See Technical Note 1: 2008 COD Collection - Process Improvements for further information.
73 In addition, the number of deaths attributed to Suicide for 2008 is expected to increase as data is subject to the revisions process.
74 Suicide deaths in children are an extremely sensitive issue for families and coroners. The number of child Suicides registered each year is low in relative terms and is likely to be underestimated. For that reason this publication does not include detailed information about Suicides for children aged under 15 years in the commentary or data cubes. There was an average of 10.1 Suicide deaths per year of children under 15 years over the period 1999 to 2008. For boys, the average number of Suicides per year was 6.9, while for girls the average number was 3.2.
75 For processing of deaths registered from 1 January 2007, revised instructions for ABS coders were developed in order to ensure consistency in the coding of suicide deaths and compliance with the revised notes for coding to the undetermined intent categories. At the time that the ABS ceases processing, each coroners record on the NCIS will have a status of 'open' or 'closed' (See Technical Note 1: 2008 COD Collection - Process Improvements for further information on coroner certified deaths). The NCIS case status impacts on how deaths are coded with regard to suicides. With the introduction of the revisions process for all deaths registered from 1 January 2007, additional information received by the ABS may lead to a more specific cause of death code being assigned. Below is a summary of the suicide coding process used by the ABS.
Undetermined Intent (Y10-Y34, Y87.2)
76 Due to changes in coding rules for ICD-10 in 2007, processing of data up to and including the 2006 reference year assigned a finding of 'Undetermined Intent' only where there had been an official coronial finding of such. Other deaths where either intent was 'not known' or 'blank' on the NCIS record, were coded with an intent of 'accidental'. From 2007, a death is coded to an 'Undetermined Intent' code where the NCIS intent field is: 'could not be determined'; 'unlikely to be known'; or 'blank'. This change in coding practice has resulted in a significant increase in deaths allocated to these codes in 2007 and 2008. However, it is important to note that the number of deaths attributed to 'Undetermined Intent' codes for both 2007 and 2008 will decrease. See Technical Note 2: Causes of Death - Revisions Process for further information.
CONFIDENTIALISATION OF DATA
77 Data cells with small values have been randomly assigned to protect confidentiality. As a result some totals will not equal the sum of their components. It is important to note that cells with 0 values have not been effected by confidentialisation.
EFFECTS OF ROUNDING
78 Where figures have been rounded, discrepancies may occur between totals and sums of the component items.
79 This publication draws extensively on information provided freely by the state and territory Registrars of Births, Deaths and Marriages, and the Victorian Institute of Forensic Medicine who manage the NCIS. Their continued cooperation is very much appreciated: without it, the wide range of vitals statistics published by the ABS would not be available.
80 Other ABS publications which may be of interest are outlined below. Please note, older publications may be available through the state and national libraries. All publications released from 1998 onwards are available on the ABS website <https://www.abs.gov.au>.
Australian Demographic Statistics, cat no. 3101.0
Australian Social Trends, cat. no. 4102.0
Births, Australia, cat. no. 3301.0
Causes of Deaths, Australia: Summary Tables, cat. no. 3303.0.55.001
Deaths, Australia, cat. no. 3302.0
Deaths From External Causes, Australia - 1998 to 2002, cat. no. 3320.0
Demography Working Paper 2004/3 - Calculating Experimental Life Tables for Use in Population Estimates and Projections of Aboriginal and Torres Strait Islander Australians, 1991 to 2001, cat. no. 3106.0.55.003
Drug Induced Deaths, cat. no. 3321.0.55.001
Experimental Estimates and Projections, Aboriginal and Torres Strait Islander Australians, 1991 to 2009, cat. no. 3238.0
Information Paper: External Causes of Death, Data Quality, 2005 (cat. no 3317.0.55.001)
Information Paper: ABS Causes of Death Statistics: Concepts, Sources, and Methods, 2006 (cat. no. 3317.0.55.002)
Information Paper: Cause of Death Certification, Australia, 2008 (cat. no. 1205.0.55.001)
Mortality Atlas, Australia, 1997 to 2000, cat. no. 3318.0
Multiple Cause of Death Analysis, 1997-2001, cat. no. 3319.0.55.001
Population Projections, Australia, 2005 to 2101, cat. no. 3222.0
Recent Developments in the Collection of Aboriginal and Torres Strait Islander Health and Welfare Statistics, 2005, cat. no. 4704.0.55.001
Suicides: Recent Trends, Australia, 1993 to 2003, cat. no. 3309.0.55.001
The Health and Welfare of Australia's Aboriginal and Torres Strait Islander Peoples, 2008, cat. no. 4704.0
81 ABS products and publications are available free of charge from the ABS website <https://www.abs.gov.au>. Click on Statistics to gain access to the full range of ABS statistical and reference information. For details on products scheduled for release in the coming week, click on the Future Releases link on the ABS homepage.
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