Coronial Study - Coding systems available
Coding systems available for death and injury event coding
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Only NSW and Vic. routinely code information for computerised
retrieval. Some limited coding of type of case has been used
in Tas.
There are two information systems operating in Vic. The Victorian
coroner's system and the Institute of Forensic Pathology's system
code cases according to three groups of codes. The first classifies
events into homicide, suicide, accident, natural and other or
undetermined. The second describes circumstances surrounding
death. Within this group multiple choices can be used and some
coverage of setting, contributing factors and place of death is
included. The third identifies a number of common causal and
significant contributing factors, with multiple coding allowed.
While this system provides useful information, it is far from
comprehensive, and category divisions within axes are not always
clear. It is also not consistent with the statistical reporting
of death required internationally by agreements with the World
Health Organization. Three years of deaths data have been coded
in the Caseflow Analysis Section of the Courts Management Division.
This system has obtained access to individual cases and extensive
coding has been undertaken. The coding system is multi-axial,
and based substantially on the ISIS coding system discussed below.
It covers common demographic categories, manner of death, intent,
activity precipitating event, mechanism of injury, factors associated
with the death, ICD external causes code and location. It is
by far the most extensive statistical database on coroner investigated
deaths in Australia.(1)
NSW utilises a number of classifications. These include the type
of death suggested by evidence, the type of death found in coroner's
inquest finding, a broad manner of death code which contains 36
categories identifying common types of death such as overdose
by one or more drugs, overdose by one or more drugs and alcohol,
gassing from car exhaust, etc. A separate code group covers manner
of slaying and a further 20 codes describe manner of suicide.
In addition, country of birth is coded, drugs found in toxicological
examination are coded in detail, as is marital status. This system
includes many duplications between code groups and does not easily
separate out the activity at time of death, the factors involved
in death or the intent. It has been developed as an administrative
aid and is difficult to use for finding groups of cases or undertaking
reliable statistical reporting.
The International Classification of Diseases (ICD9) in its ninth
revision is used in Australia and by the World Health Organization
to classify death and hospital inpatient morbidity cases. It
forms the basis for national reports on mortality produced by
the ABS. Two parts of the classification are relevant for a coronial
information system.
The first is the classification of external causes of injury.
This system forms a single axis and describes circumstances leading
to accidental and intentional deaths. Suicide and homicide are
classified under separate code groups which results in loss of
detail compared to unintentional deaths by the same means, especially
in the case of poisoning. Type of place is also coded under
a separate code group. The level of detail of this system is
inconsistent and does not properly separate activity, place of
death and factors contributing to the death. It is impossible,
for example, to identify type of machinery, or the role of a consumer
product. Information in the coroner's system is adequate for
coding the external cause and this is already done by the ABS.
The second coding axis is the physical nature of disease or injury.
This is a detailed classification system which has been used
as a basis for a number of injury severity scores, especially
in the field of motor vehicle related injury. This set of codes
is more consistent than the external causes code system, but is
not currently used in cause of death statistics in Australia.
This is a major deficiency. The description of anatomical findings
at autopsy is not always specific enough, or in the terminology
necessary for ICD coding, and extensive work is necessary to code
this information from autopsy findings.
The ISIS system is a multi-axial coding system specifically developed
for the coding of information about injury cases presenting to
hospital emergency departments by the National Injury Surveillance
and Prevention Project. The axes are as follows:
Location
Activity at time of injury
Text description of events leading to injury
What went wrong event code
Factors and products involved in what went wrong
Mechanism of injury
Factors and products involved in the injury event
Intent
Safety measures being used
Motor vehicle seating position
Nature of injury
Body part
Job status (on or off the job)
Factor codes are based on the United States Consumer Product Safety
Commission codes, expanded to cover industrial equipment, natural
features and other non-product factors. In addition, standard
demographic information is collected. This system proved too
complex for sustainable use in a wide range of emergency departments
and the NMDS(IS) system has been developed for this purpose.
Some axes have been limited for emergency department use, including
the nature of injury and body part classification which provides
only a limited level of anatomical information. Refinements of
the breakdown and mechanism coding systems have been suggested
to define a longer chain of events. In the coroner's setting,
where detailed investigations are made, elements of this system
could provide a useful indexing and statistical reporting function.
ISIS codes are not easily recoded to ICD codes.
NISU(2) proposes the use of an NMDS(IS) as a minimum standard, capable
of identifying major categories of interest, and of being applied
to the various major sources of data including mortality, hospital
inpatient morbidity and emergency department cases etc. The NMDS(IS)
a multi-axial system covering:
Type of place
Activity
A text based event description
Human intent
Nature of injury
Body part
Geographic location of injury event
Broad ICD external causes categories or fill ICD9 E-code
The NMDS(IS) system is less detailed than ISIS and, in some respects,
than ICD codes. It has the advantage over ICD of having better
conceptual clarity and separate axes and, in some areas, it carries
more detail.
There are a number of road fatality and injury information systems
across Australia. FORS compiles a database from police that contains
a common set of information. This is less than is desired by FORS,
but is limited by what is possible in each State. Variables are
coded according to a number of agreed protocols. Information on
the needs of the road sector details the major variables.
Worksafe Australia has specified variables which it requires for
the study of work related fatalities and these are found in the
user needs section of this report. Worksafe also uses a coding
system called the 'Type of Occurrence' classification system for
categorising injury events. This system was introduced as part
of the development of the National Data Set for Compensation Based
Statistics. It includes the following axes.
Nature of injury / disease,
Bodily location of injury / disease,
Mechanism of injury / disease,
Agency
The coding system assumes that multiple injuries and multiple
agencies will occur and these are coded according to seriousness
of injury and the temporal order of agencies, starting with the
critical or breakdown event. The system is designed for use in
workers' compensation cases and therefore limits the specificity
of the coding system to the level possible in this setting.
(1) State Coroner's Office Victoria, Unnatural Deaths: Collated
Findings of the State Coroner Vol 1 1989-90, Vol 2 1990-1991,
Melbourne State Coroner's Office, Victoria, 1993, 1994.
(2) Harrison J and Tyson D, Preventing injury, in Selby H (Ed.),
The Aftermath of Death, Leichhardt Federation Press, 1992,
Chapter 16
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