Methods

The aim of this report is to count the number of hospitalisations and deaths that were due to alcohol-related injury in Australia from 1 July 2019 to 30 June 2020. In all cases, patients had both an injury condition and an alcohol-related condition (see Box 1) recorded in their hospital record, or an injury-related and an alcohol-related cause of death recorded.

Box 1: What does ‘alcohol-related’ mean?

Some health conditions can be entirely attributed to, or caused by, alcohol (for example alcoholic liver disease) – these conditions are sometimes referred to as ‘alcohol-induced’ conditions (Chikritzhs et al. 2002).  

Other health conditions are only partially attributed to, or caused by, alcohol (for example a car accident or assault). These are sometimes referred to as ‘alcohol-related’ conditions, and the level of alcohol contribution may vary due to different factors (for example the quantity of alcohol consumed and frequency of consumption) (Chikritzhs et al. 2002).

Determining the extent to which alcohol caused or contributed to an injury event was a challenge in this project. For this reason, this report examines both alcohol-related and alcohol-induced injuries and uses the term ‘alcohol-related’ to refer to all cases, regardless of the extent to which alcohol may have contributed to the injury event.

Unlike jurisdictional and hospital data records, the National Hospital Morbidity Database (NHMD) does not contain text fields: diagnosis and external-cause-of-injury information is restricted to International Statistical Classification of Diseases and Related Health Problems Tenth Revision Australian Modification (ICD-10-AM) codes. The data quality therefore depends on the extent to which hospital staff record the involvement of alcohol and the completeness with which those notes are coded by hospital coders.

The deaths data used in this report comes from the National Mortality Database (NMD), which contains information on all deaths certified by a doctor or coroner. The NMD, like the hospitalisations data, contains coded fields, meaning the cause of death and external cause of injury information is restricted to the ICD-10 classification system coding (ABS 2020).

Deaths that are unexpected are certified by a coroner; these deaths are included in the National Coronial Information System (NCIS) database. The NCIS contains both text and coded information on the circumstances surrounding the death. A large proportion of alcohol-related injuries are certified by a coroner. These deaths are included in both the NMD and the NCIS data (NCIS 2020), however because coronial investigations can take some time to conclude, there may be a time lag between a death and the record being included in the data sets.

This report uses NHMD data to investigate the number of alcohol-related injury hospitalisations and both the NMD and NCIS data to examine the number of alcohol-related injury deaths in Australia for 2019–20.

A limitation of this report is that it does not include information on cases that did not result in hospitalisation or death. For each hospitalisation or death there are many more cases that are treated by emergency departments, general practitioners, allied health professionals or outpatient clinics.

Cases where a patient was transferred between hospitals or where a patient’s care type changed while in hospital were only counted once.

Deaths that occurred during hospitalisation may be counted in both the hospitalisations and deaths data.

Defining injury

For the purposes of this report, injury is defined by diagnosis codes (in the ICD-10-AM classification system for hospitalisations) and cause-of-death codes (in the ICD-10 classification system for deaths) within the range S00–T75 and T79 as per Box 2 (ACCD 2017; WHO 2019).

Box 2: In-scope injury categories

S00–S09          Injuries to the head

S10–S19          Injuries to the neck

S20–S29          Injuries to the thorax

S30–S39          Injuries to the abdomen, lower back, lumbar spine and pelvis

S40–S49          Injuries to the shoulder and upper arm

S50–S59          Injuries to the elbow and forearm

S60–S69          Injuries to the wrist and hand

S70–S79          Injuries to the hip and thigh

S80–S89          Injuries to the knee and lower leg

S90–S99          Injuries to the ankle and foot

T00–T07          Injuries involving multiple body regions

T08–T14          Injuries to unspecified part of trunk, limb or body region

T15–T19          Effects of foreign body entering through natural orifice

T20–T31          Burns

T33–T35          Frostbite

T36–T50          Poisoning by drugs, medicaments and biological substances

T51–T65          Toxic effects of substances chiefly nonmedicinal as to source (including alcohol)

T66–T75          Other and unspecified effects of external causes

T79–T79          Certain early complications of trauma

Defining alcohol-related conditions

The ICD-10-AM and ICD-10 contain many codes for health conditions and causes of death related to alcohol use. We included only those that were most likely to provide evidence that drinking alcohol contributed to the occurrence of the injury, as per Box 3 (ACCD 2017; WHO 2019).

Box 3: In-scope alcohol-related conditions

F10.0   Acute alcohol intoxication

F10.1   Harmful use of alcohol

F10.2   Alcohol dependence syndrome

R78.0   Finding of alcohol in the blood

T51.0   Toxic effect of alcohol (ethanol)

T51.9   Toxic effect of alcohol (type unspecified) poisoning

X45      Accidental poisoning by and exposure to alcohol

X65      Intentional self-poisoning by and exposure to alcohol

Y15      Poisoning by and exposure to alcohol, undetermined intent

Y90      Evidence of alcohol involvement determined by blood alcohol level (used in hospitalisations data only; not used in deaths data)

Z72.1   Problems related to lifestyle – alcohol use 

Some of these codes (T, X and Y codes) overlap with the injury definition above because poisoning by alcohol is defined as an injury in the ICD-10-AM and ICD-10.

Exclusions

We excluded alcohol-related codes used in other studies of alcohol-related harm (for example, AIHW 2022, McKenzie et al. 2010, Nguyen et al. 2018):

  1. that are assigned for other non-injury health conditions associated with alcohol (for example - K70 Alcoholic liver disease)
  2. that relate to non-beverage types of alcohol (for example - T51.1–51.8 Methanol)
  3. that relate to alcohol counselling and surveillance services (for example - Z71.4 Counselling and surveillance for alcohol use disorder)
  4. where there is a coding note in the ICD-10-AM instructing that the code should not be used (for example - Y91 Evidence of alcohol involvement determined by blood alcohol level)
  5. where the likelihood of alcohol use being a direct contributor to the injury occurring was deemed to be lower (for example - F10.3   Withdrawal state due to use of alcohol).

While an argument could be made for including F10.3 and other similar codes, these were excluded on the basis that it is more difficult to assume that the person was under the influence of alcohol when they were injured compared to the F10.0–F10.2 codes that were included. Including these cases would have yielded an extra 3,230 hospitalisations and 5 deaths.

Inclusion criteria

Box 4: Key definitions

The principal diagnosis is established after study to be chiefly responsible for occasioning an episode of admitted patient care (AIHW METEOR).

Additional diagnoses are the one or more conditions or complaints either coexisting with the principal diagnosis or arising during the episode of admitted patient care (AIHW METEOR).

External cause is the circumstance in which an injury, poisoning or other adverse effect has occurred (AIHW METEOR).

Underlying cause of death is the disease or injury that initiated the train of morbid events leading directly to a person’s death or the circumstances of the accident or violence which produced the fatal injury (AIHW METeOR).

Multiple causes of death (or associated causes of death) are the one or more morbid conditions, diseases and injuries which are listed on the death certificate. They include all the factors in the morbid train of events leading to death: the underlying cause, the immediate cause, any intervening causes, and any conditions that contributed (AIHW METEOR).

Mechanism of injury is the means, environmental event, condition, or circumstances in which the injury sustained resulted in death. Mechanism of injury is similar to the concept of external cause, but usually excludes the concept of intent (NCIS 2020).

Object or substance producing injury means objects, substances and phenomena which produce injury/ies causing death (NCIS 2020).

Hospitalisations

Box 5: Inclusion criteria for hospitalisations

Records were included in the analysis where there was:

Criterion 1 (28,036 cases):

a principal diagnosis of injury (S00-T75; T79) and:

an additional in-scope diagnosis relating to alcohol use (F10.0, F10.1, F10.2, R78.0, T51.0,
T51.9, Z72.1) or

there was an external cause of injury related to alcohol use (X45, X65, Y15, Y90)

OR

Criterion 2 (1,988 cases):

a principal diagnosis of acute alcohol intoxication (F10.0) and an additional diagnosis of injury (S00-T75; T79).


See technical notes for further information on the counts contributed by each criterion and ICD-10-AM code (ACCD 2017).

Criterion 2 was included to incorporate cases where there was definite evidence of both alcohol intoxication and injury at the time of hospital admission, where the alcohol intoxication was the chief reason for admission. The principal diagnosis in criterion 2 is restricted to acute alcohol intoxication (F10.0) and does not include the 547 cases where harmful use of alcohol (F10.1) or alcohol withdrawal state (F10.2) was the principal diagnosis. Although an argument could be made for including these cases, these were excluded because of the reduced certainty of alcohol being involved in the occurrence of the injury.

Deaths

    Box 6: Inclusion criteria for deaths 

Records from the National Morbidity Database (NMD) were included in the analysis where (WHO 2019):

Criterion 1 (143 cases):

there was an alcohol-related underlying cause of death of:

accidental poisoning by and exposure to alcohol (X45) or

intentional self-poisoning by and exposure to alcohol (X65) or

poisoning by and exposure to alcohol, undetermined intent (Y15)

OR

Criterion 2 (1,721 cases):

there was an injury-related cause of death (S00–T75; T79) and

there was an injury-related external cause of death (V01–Y36) and

there was an in-scope alcohol-related cause of death (F10.0, F10.1, F10.2, R78.0, Z72.1)

OR

Criterion 3 (491 cases):

there was an in-scope alcohol-related injury cause of death (T51.0, T51.9) and

there was an injury-related external cause of death (V01–Y36)

OR

Criterion 4 (280 cases):

there was an injury-related cause of death (S00–T75; T79) and

there was an in-scope alcohol-related external cause of death (X45, X65, Y15).


Records from all Australian states and territories in the National Coronial Information System (NCIS) were included in the analysis where (740 cases):

the death occurred from 1 July 2019 to 31 December 2019 and

the case status was ‘Closed’ and

the case type was ‘Death due to external causes’ and

the object or substance producing injury was ‘Pharmaceutical substances for human use’ and

the parent drug was ‘Alcohol’.

Alcohol and drug contribution level in the NCIS

NCIS data classifies alcohol as either a primary or secondary contributor to a death.

A substance is considered to have a primary contribution to a death where:

drug toxicity is noted within the primary mechanism and object field or

aspiration of gastric contents is noted in the primary mechanism and object field and drug toxicity was noted in the secondary mechanism and object field.

A substance is considered to have a secondary contribution to death where:

another external mechanism (such as a vehicle incident, a fall or drowning) is noted within the primary (and, where required, secondary) mechanism and object field, and

pharmaceutical drug toxicity is noted within the secondary or tertiary mechanism and object field.

If pharmaceutical substances contributed to the death, all drugs identified are recorded. For example, where oxycodone toxicity is noted in the cause of death and alcohol is also identified, both substances are recorded in the relevant drug field.

Cases where alcohol is either the primary or secondary contributor to the death were in scope for this report. See the Technical notes for further information the NCIS data.

Limitations

Ability to ascertain involvement of alcohol in the injury event

In preparing this report, subject-matter and ICD-10-AM experts were consulted with the aim to identify cases with ICD codes that provide reasonable confidence that the person was under the effect of alcohol when they were injured. However, there is no one accurate way to do this and the authors acknowledge that the data may include:

  • cases where alcohol was consumed after the injury event
  • cases where alcohol was consumed, however it did not contribute to the injury event

and may exclude:

  • cases where alcohol use contributed to an injury event, but by the time the person presented to hospital, the alcohol consumption was not detectable, divulged or considered relevant by the recorder and therefore was not documented in the patient record.

There are other approaches that quantify the extent to which alcohol contributed to the occurrence of an injury. For example, the alcohol attributable fractions (AAF) method estimates the proportion of injury that would be removed if there were no alcohol consumption. AAFs are used by the World Health Organization in burden-of-disease estimates (Cherpitel et al. 2015, Taylor et al. 2011, Chikritzhs et al. 2002). However, to calculate the AAF, a reference group (of non-drinkers or low-risk drinkers) is required and information on drinking habits is not available within the NHMD (Chikritzhs et al. 2002). Instead, this report uses broadly the same methodology used in other AIHW injury reports (such as Injury in Australia).

Ability to identify injuries sustained relating to someone else’s use of alcohol

The available data can only identify cases where the injured person had consumed alcohol. It is not able to identify cases where another person’s use of alcohol contributed to the injury of the person who was hospitalised or died. For example, where someone is assaulted by a person under the influence of alcohol.

Evidence of under-recording of the involvement of alcohol in the NHMD

McKenzie et al. (2010) found that counting alcohol involvement in hospitalisations using ICD-10-AM codes alone only identified 38% of cases. In contrast, 94% of cases were identified by using a text search of medical records. McKenzie et al.’s inclusion criteria were broader than this report – they included cases of chronic disease associated with long-term excessive alcohol use.

Lau et al. (2021) also found that ICD-10-AM coding underestimated the proportion of injury events involving alcohol, compared to patient blood alcohol testing – while 15% of patients had a non-zero blood-alcohol concentration, only 4% had an ICD-10-AM code suggesting acute alcohol involvement. Only 37% of patients with a positive blood-alcohol concentration had an alcohol-related ICD code, even though 80% of patients had a blood alcohol concentration of over 0.05 recorded.

Emergency department presentation

This report does not include data from emergency department datasets, as the data quality of national ED data does not currently enable reliable identification of alcohol-related injury presentations.

NCIS time delay

NCIS data is via the NCIS data report service was available for analysis later than the NMD due to the time taken to finalise coronial investigations. At the time of writing, NCIS data for 2020 was not available via the NCIS data report service. Therefore, analysis of the NCIS database from 1 July 2019 to 31 December 2019 (6 months) is included to supplement the information in the NMD but is not representative of the full reporting period (2019–20).

Other limitations of the NHMD and the NMD are explained in the technical notes.

Examples of how the inclusion criteria applies

The three fictional examples below show how the inclusion criteria used in this project apply under different circumstances. The examples are designed to give readers a greater understanding of the diversity of alcohol-related injuries among Australians.

Example 1: Lee’s story

Lee works in a sales role with regular business dinners involving alcohol. One Friday night after closing a deal over dinner, Lee celebrated with co-workers at a bar with further drinks. After consuming approximately 7 standard drinks over a period of 3 hours, Lee headed home, thinking, ‘I feel okay. I’ll be fine to drive’. On the way home Lee lost control of the car and crashed into a tree.

Lee was taken to hospital by ambulance and was admitted with an open wound to the head (S01 - the primary reason for admission) and a fractured forearm (S52). The medical professionals identified acute alcohol intoxication and noted this in the medical record (F10.0).

De-identified data about Lee’s hospitalisation would be included in the scope of this report based on the above criteria.

Example 2: Jordan’s story

Jordan is a university student in a regional city. Jordan has bouts of depression and since beginning university, Jordan’s alcohol consumption has increased, and they sometimes experiment with other drugs.

At a Saturday night party, Jordan drank more alcohol than usual (12 standard drinks) and took benzodiazepines (a depressant drug) with the intent to cause themselves harm. Jordan’s friends noticed them fading in and out of consciousness and their body became increasingly cold. An ambulance was called, and they were admitted to hospital and treated primarily for the toxic effect of alcohol (T51 – injury diagnosis). Harmful use of alcohol as an additional diagnosis (F10.1 – alcohol related condition) and intentional self-harm by exposure to benzodiazepines as an external cause code (X61 – Intentional self-harm by exposure to anti-epileptic, sedative-hypnotic, anti-parkinsonism and psychotropic drugs, not elsewhere classified) were also recorded in the medical record.

De-identified data about Jordan’s hospitalisation would have been included in this report based on the above criteria.

Example 3: Ari’s story

Ari, a 30-year-old electrician enjoys a night at the pub with his workmates. One night after work Ari walked to his local pub for dinner, beers and to watch a football game. After watching his team win and consuming about 5 standard drinks, Ari started his short walk home. Walking in the dark, he tripped and hit his head on the footpath, but did not lose consciousness.  A passer-by called an ambulance and Ari was taken to the emergency department of his local hospital. After assessing Ari’s injuries, he was able to go home with recommendations to rest and seek assistance if his condition worsened.

The medical attention Ari received would not have been captured in this report as he was not admitted to hospital.