Characteristics of ex-serving Australian Defence Force members hospitalised for suicidality and intentional self-harm

Codes and Classifications for Admitted Patient Care Analysis

International Statistical Classification of Diseases and Related Health Problems, 10^th revision, Australian Modification (ICD-10-AM)

Diagnosis, intervention, and external cause data are provided to the NHMD by all states and territories using the ICD-10-AM and the Australian Classification of Health Interventions (ACHI). The Australian Coding Standards are designed to be used in conjunction with the ICD-10-AM and ACHI to support sound coding convention. Although the ICD-10-AM is primarily designed for the diseases and injuries with a formal diagnosis, it also classifies a wide variety of signs, symptoms, abnormal findings, complaints, and social circumstances that may stand in place of a diagnosis. During the study period, hospital records were coded according to the applicable ICD-10-AM edition:

• 2010–11 to 2012–13: ICD-10-AM 7th edition
• 2013–14 to 2014–15: ICD-10-AM 8th edition
• 2015–16 to 2016–17: ICD-10-AM 9th edition
• 2017–18 to 2020–21: ICD-10-AM 10th edition.

It is important to note that diagnostic classifications and coding standards have changed over time. There is also variation in the quality, completeness and depth of coding across services, and state-specific standards. These factors can impact on the accuracy of diagnostic information.

ICD-10-AM 1–4-character diagnosis codes are used to construct the diagnostic groups according to AIHW conventions for this analysis.

Excluded from this analysis were separations with the care type ‘hospital boarder’ or ‘posthumous organ procurement.

ICD-10 AM Chapter principal diagnostic groups

The ‘Chapter’ groups are the broadest diagnostic category in the ICD-10-AM for describing the reason a patient received admitted patient care. Table 13 delineates the ICD-10 AM Chapter diagnostic groups used for this analysis.

Mental health-related care

These groups were constructed in accordance with AIHW reporting conventions for mental health-related admitted patient care. Broad mental health diagnostic groups were derived from the AIHW detailed groupings to accommodate small numbers for the ex-serving ADF member cohort.

Further information on codes and classifications for mental health-related care is available on the AIHW website. Table 14 delineates the mental health diagnostic groups used for this analysis.

Intentional self-harm diagnoses

Records of hospitalisation for treatment following intentional self-harm were included if they met the following criteria:

• a principal diagnosis in the ICD-10-AM range S00-T75, T79 (Injury, poisoning and certain other consequences of external causes)
• the first reported external cause code in the record in the ICD-10-AM range X60–X84, Y87.0 (external causes of morbidity).

The term ‘intentional self-harm’ in the National Hospital Morbidity Database (NHMD) provides information on patients admitted to hospital for self-poisoning or self-injury, with or without suicidal intent – and therefore includes both suicide attempts and non-suicidal self-harming behaviours.

Counts of hospitalisations for intentional self-harm reported may differ slightly from other publications. This reflects differences in the inclusion and/or exclusion criteria (e.g. rehabilitation) and multi-episode stay-based rather than single episode-based analysis. At least one episode in multi-episode stays had to meet the above criteria to be included in the intentional self-harm patient group. This diagnostic group had negligible (<0.1%) stays containing episodes with a principal or additional diagnosis of ‘care involving the use of rehabilitation procedures’ (Z50).

Further information about codes and classifications related to intentional self-harm is available on the AIHW website.

Alcohol and other drug diagnoses

These groups were constructed in accordance with AIHW reporting conventions. Broad diagnostic groupings of physical and mental-health related conditions related to the use of alcohol and other drugs were constructed. This was to accommodate small numbers in the ex-serving ADF cohort.

Further information about the codes and classifications used by AIHW for the alcohol and other drug related diagnostic groups is available on the AIHW website. Table 16 delineates the diagnostic groups used for this analysis.

National Death Index (NDI) causes of mortality

Causes of mortality included in the NDI are recorded as ICD-10 codes, as derived by Australian Bureau of Statistics from death certificates. Causes of mortality have been grouped according to ICD-10 chapter. Subgroups have been created (where there is sufficient data) for ‘intentional self-harm,’ ‘deaths of despair’ and ‘deaths of undetermined intent.’ Deaths from intentional self-harm are a subgroup of deaths of despair. Table 17 provides further information.

Codes and Classifications for Emergency Department Care Analysis

During the study period, ED records were coded by hospitals according to a code sets, the range of codes available varied from hospital to hospital and between jurisdictions. The ED data comprise 3 fields only, into which the patient’s treating clinician can apply diagnoses to the electronic record at the conclusion of a patients ED presentation. In contrast to the admitted patient coding, these fields are not input by trained medical records coders. 

The principal diagnosis is established at the conclusion of the patient's attendance in an ED and is to be the main diagnosis responsible for occasioning the attendance following consideration of clinical assessment by a coder. The first additional diagnosis is the first condition or complaint coexisting with the ED principal diagnosis during a patient's attendance to the ED, as represented by a code. The second additional diagnosis is the second condition or complaint coexisting with the ED principal diagnosis during a patient's attendance to the ED, as represented by a code. Due to the limited code positions and depth of coding, it cannot be assumed that the patient does not have a particular condition if it is not recorded.

In the NHDH each of these 3 fields are available from 2013–14 onward. Care must be taken when evaluating these diagnoses over time, as diagnosis information was supplied using different classifications for all study years. For years 2013–14 to 2017–18, the following code sets were able to be used for this field: 

• ICD-10-AM (6th, 7th, 8th, and 9th editions)
• ICD-9-CM (2nd edition)
• EDRS-SNOMED CT-AU

From 2018–19, an ICD-10-AM based 'ED shortlist' was used for the principal diagnosis field (METEOR identifier 681646).

Each of these code sets are further described below.

International Statistical Classification of Diseases and Related Health Problems, 10^th revision, Australian Modification (ICD-10-AM)

Although the ICD-10-AM is primarily designed for the diseases and injuries with a formal diagnosis, it also classifies a wide variety of signs, symptoms, abnormal findings, complaints, and social circumstances that may stand in place of a diagnosis. 

It is important to note that diagnostic classifications and coding standards have changed over time, hence their numerated editions. There is also variation in the quality, completeness, and depth of coding across services, and state-specific standards. These factors can impact on the accuracy of diagnostic information.

Systemised Nomenclature of Medicine - Clinical Terms - Australia (SNOMED CT-AU)

The Systemised Nomenclature of Medicine – Clinical Terms – Australia (SNOMED CT-AU) is the Australian extension of SNOMED CT, a comprehensive multilingual health terminology. SNOMED CT is designed to underpin clinical data recording and meaning-based retrieval and use. SNOMED includes more than 350,000 active concepts with unique meanings and formal logic-based definitions, organised in hierarchies with multiple levels of granularity. The hierarchies include clinical findings, procedures, observables, body structures, organisms, substances, and pharmaceutical/biologic products.

Emergency department ICD-10-AM (10th ed) principal diagnosis Short List

The ICD-10-AM Emergency Department Principal Diagnosis Short List was developed in 2015 by the Independent Hospital and Aged Care Pricing Authority (IHACPA) from the full version of ICD-10-AM. The short list was compiled using data analysis and clinical advice. The ED Short List replaces previous reporting inconsistencies whereby states and territories would report principal diagnosis using various code sets, including SNOMED CT, ICD-9-CM, or the various versions of ICD-10-AM. 

The ED Short List does not contain any of the external cause codes from the ICD-10-AM, therefore the code range that is commonly used to identify intentional self-harm (X60-X84, Y87.0) are not included. The ICD10-AM code for suicidal ideation (R45.81) is included in the Short List.

IHACPA has developed mapping files between each version of the ED Short List (9, 10 and 11 to date) and the full ICD-10-AM. IHACPA has also developed a mapping file between the full ICD-10-AM and SNOMED-CT-AU, which they provided the AIHW for the purposes of these analyses. 

Codes defining intentional self-harm and suicidal ideation

Given the known challenges and limitations of the identifying suicidal behaviours within the ED data, as well as the variability in code sets used – which varies within jurisdictions, this project further aimed to enhance the identification of both the cohort of interest and the comorbid risk factors associated using three methods. Firstly, we used a method developed and validated by NSW Health System Information and Analytics Branch (Sara and Wu 2023), which is now routinely used across NSW for the purpose of better identifying suicide and self-harm presentations to the Emergency Department. Secondly, we used the mapping file provided by IHACPA to add any additional codes across all diagnoses of interest, and thirdly, for the enhanced identification of patients presenting with alcohol use disorders, we used the method described by Zhang et al. (2022). 

The suicidal ideation and self-harm population analysed in this report included any person presenting to any ED in Australia, with any diagnosis (that is in any of the 3 diagnosis code positions), with either intentional self-harm and/or suicidal ideation, identified by any of the codes below. 

Intentional self-harm 

Records of ED presentation for treatment following intentional self-harm were included if they contained any of the following codes (Table 18), noting that ICD10-AM codes were included both with and without a decimal place, to accommodate variation in coding practices.

Suicidal ideation

Records of an ED presentation for suicidal ideation were included if they contained any of the following codes (Table 19).

Codes used to define diagnoses for risk factors associated with self-harm and suicidal behaviour

Military service-related characteristics

Table 21 provides information about ADF service characteristics that are used for this analysis.

DVA clients 

In the general sense, DVA clients include serving, reserve, or ex-serving ADF members, or a partner or their dependents who receive support from DVA. A DVA client can be a DVA card holder, a benefit or income recipient and/or a user of health services or support services funded by DVA. The definition in this report is limited to ex-serving ADF members.

DVA client definition

A DVA client under the broad definition used in this report is an ex-serving ADF member who satisfies at least one of the following criteria:

• has been issued a White, Orange or Gold card
• had at least one accepted claim for a health or disability condition accepted as being related to service
• has received or is receiving benefits or payment
• had at least one health service or support service through the DVA National Treatment Account.

This definition does not include ex-serving ADF members who had made only rejected DVA claims and were not a card holder or in receipt of any benefits from DVA.

For this analysis, additional subgroupings of DVA clients are reported based on the type of card held by the client (if any):

• Gold card holder – has a DVA Gold card (regardless of other concurrent card types)
• White card holder – has a DVA White card but not a Gold card
• Other – has a DVA Orange card (but no Gold or White card) or no DVA card

Veteran Gold Cards

Holders of a Gold Card are entitled to DVA funding for all clinically necessary health services related to all health conditions, regardless of whether they were related to service.

Veteran White Cards

White Card holders are entitled to health services related only to conditions accepted as relating to service. However, cases of malignant cancer, pulmonary tuberculosis, and any mental-health condition do not have to be due to service-related causes.

From 1 July 2018, eligibility for treatment of any mental health condition expanded to include Reservists who have rendered Reserve Service Days with disaster relief service, border protection service or involvement in a serious service-related training incident. In addition, the White Card on Transition project commenced, with DVA issuing White Cards to transitioning members as they separate from the ADF.

Veteran Orange Cards

Orange Card holders are entitled to access prescription medicines, wound care items and nutritional supplements at a concession rate. Orange cards cannot be used for medical or other healthcare treatment. A Veteran Orange Card is issued to Commonwealth and allied veterans and mariners who meet all the following:

• They have qualifying service from the First World War or the Second World War.
• They are aged 70 or over.
• They have been resident in Australia for 10 years or more.

More information about DVA services and entitlements is available at Overview of DVA benefits and services.