Injury related presentations to Emergency Departments
The first time injury related emergency department (ED) presentations are described is in 2022–23.
Emergency department (ED) care is a form of non-admitted hospital care. While emergency department presentation records have many of the same fields as hospital records, there are key differences in the way they are structured.
A notable difference in ED records compared with hospitalisations and deaths, is the lack of external cause data. External cause and related data on the injury include details such as place of occurrence, mechanism of the injury, activity being undertaken at the time, intent and perpetrator. Additionally, there are unique variables only found within ED records such as triage category and waiting time that cannot be compared against hospitalisations and deaths.
Emergency department presentations for injury incidents are generally more numerous than the number of hospitalisations. This is because many injuries can be treated in emergency departments and do not require admission to a hospital. Many more people with injuries are treated outside of a hospital such as at a general practice – these injuries are not captured in ED data.
For summary of key data quality issues affecting ED data, please refer to the interactive timeline in Figure 1.
Injury case identification
An ED presentation for an injury is defined where the following apply:
- An ED record is present with a principal diagnosis of ICD-10-AM codes in the range S00–T75 or T79. In 2022-23, about 94% of injury related ED records had the injury recorded as principal diagnosis for presentation, about 6% had an additional diagnosis of injury recorded, with or without a principal diagnosis of injury.
- The presentation date and time are between midnight of 1 July and midnight of 30 June of the financial year of reporting.
- A person may have more than one injury recorded during a presentation, if both principal and additional diagnoses include injuries, that presentation is counted once.
- Cases that are hospitalised after presenting to emergency departments are counted in both ED and hospitals data sources.
- A small number of severe injuries result in the person being dead on arrival at the emergency department, these cases are counted in both the ED and deaths data sources.
This scope excludes injuries due to Complications of surgical and medical care (T80 – T88) and Sequelae of injuries, of poisoning and of other consequences of external causes (T90 – T98) in line with our reporting on injury hospitalisations.
Definitions and classifications
If not otherwise indicated, data elements were defined according to their definitions in the AIHW’s Metadata Online Registry (METEOR) and summarised in the Glossary.
In particular, data element definitions for the Non-admitted patient emergency department care National Minimum Data Set (NMDS) are available online at: METEOR website.
External cause data
The NNAPEDCD does not include a field for external cause of injury (such as a fall or transport accident) or other related data such as place of occurrence, mechanism of the injury, activity being undertaken at the time, intent and perpetrator. Australian injury surveillance systems have a major focus on the external causes of injuries, which is especially important from a prevention perspective. The absence of these national data obstructs direct comparisons between the causes of injury across hospitalisations, deaths, and ED presentation data.
Reporting diagnosis information
For the 2022–23 NAPEDC NMDS/NBEDS, diagnosis information was reported using the ED ICD-10-AM version 11 shortlist that can be found on the website of the Independent Hospital Pricing Authority. From 2020–21, the short list was based on ICD-10-AM version 11.
Episode end status
There is a difference between the number of presentations with a type of visit of Dead on arrival and the number of presentations with an episode end status of Dead on arrival. All presentations with a type of visit of Dead on arrival had an episode end status of Dead on arrival. However, some presentations with an episode end status of Dead on arrival did not have a type of visit of Dead on arrival.
Waiting time to commencement of clinical care
The waiting times are determined as the time elapsed between presentation to the emergency department and the commencement of clinical care. The calculation is restricted to presentations with a type of visit of Emergency presentation, and presentations were excluded if the waiting time was missing or invalid, or if the patient Did not wait to be attended by a health care professional, was Dead on arrival or Registered, advised of another health service and left without being attended to.
Proportion of presentations seen on time
The proportion of presentations seen on time was determined as the proportion of presentations in each triage category with a waiting time less than or equal to the maximum waiting time stated in the Australasian Triage Scale definition. Triage categories and respective clinically appropriate waiting times are described in Table 1 (for further details see AIHW METEOR).
| Category | Clinically appropriate waiting time |
|---|---|
1: Resuscitation | Immediate (within seconds) |
2: Emergency | Within 10 minutes |
3: Urgent | Within 30 minutes |
4: Semi-urgent | Within 60 minutes |
5: Non-urgent | Within 120 minutes |
For Injury in Australia, a patient with a triage category of Resuscitation is considered to be seen on time if the waiting time to commencement of clinical care is less than or equal to 2 minutes.
Quality of data on ED waiting times
The criteria used to determine the proportion of Resuscitation patients seen on time varies between jurisdictions, therefore, the proportions of Resuscitation patients seen on time may differ from those reported by individual jurisdictions.
Proportion of presentations ending in admission
The proportion of presentations ending in admission is determined as the proportion of all emergency presentations with an episode end status of Admitted to this hospital (either short-stay unit, hospital-in-the-home, or non-emergency department hospital ward).
Analysis methods
The Australian ERP as at 30 June 2001 is used as the standardising population throughout the report. Age‑standardisation of rates enables valid comparison across years and/or jurisdictions without being affected by differences in age distributions.
Population‑based rates of injury tend to have similar values from one year to the next. Exceptions to this can occur (for example, due to a mass‑casualty disaster), but are unusual in Australian injury data. Some year‑on‑year variation and short‑run fluctuations are to be expected, so small changes in a rate over a short period do not provide a firm basis for asserting that a trend is present.
All rate calculations (Table 2) utilise a denominator based on the estimated resident population (ERP) calculated as at the midpoint of each financial year. For example, for the reporting period 2022–23, the denominator population is the June 2022 ERP + the June 2023 ERP, divided by 2. This is used as the denominator for age‑specific/crude and age‑standardised rates. Rates are calculated for each financial year unless otherwise noted.
| Measure | Numerator | Denominator | Calculation |
|---|---|---|---|
Population (used for rates) | June 2022 population + June 2023 population | 2 | Numerator ÷ Denominator |
Crude or age-specific rate | Number of injury ED presentations per defined category (e.g. age group) | Estimated Australian population as at mid-point of financial year | (Numerator ÷ Denominator) x 100,000 |
Age-standardised rate (ASR). ASRs were derived using 5-year age groups up to 85+. ASRs for First Nation populations were derived using 5-year age groups up to 65+. | Expected events per age group in standard population= crude rate x standard population (for each corresponding age group) | n.a. | The direct method of standardisation is used. (Sum of numerators across all age groups ÷ total standard population) x 100,000 |
Change in rates | n.a. | n.a. | Estimated trends in age-standardised rates were reported as average annual percentage changes. |
n.a. Not Applicable
Timeseries
10-year time series rates may not match historically published rates due to changes in denominator data over time, jurisdictional updates in numerator data or retrospective refreshing of numerator or denominator data across different data sources.
Presentation of data
An ED presentation may have more than 1 recorded injury, each presentation has been counted once if it has multiple injuries recorded.
Persons totals include presentations for which sex was not reported.
All age totals include presentations where age was not reported.
Crude/age-specific rates and age-standardised rates are calculated per 100,000 population and are rounded to 1 decimal place (e.g. 3.4 per 100,000).
Data suppression and confidentiality
Data (cells) in tables may be suppressed to maintain the privacy or confidentiality of a person or organisation; or because a proportion, rate (numerator or denominator) or other measure is related to a small number of events (and may therefore not be reliable). Data may also be suppressed to avoid attribute disclosure. The abbreviation ‘n.p.’ (not published) has been used in tables to denote these suppressions. In these tables, the suppressed information is included in the totals.
Counts
Counts of under 5 are suppressed and consequential suppression is applied.
Crude rates
- Crude rates with counts (numerator for calculation) less than 10 are suppressed.
- If the corresponding counts measure is suppressed, the crude rate has been suppressed.
Age-standardised rates
- Age-standardised rates with counts (numerator for calculation) less than 20 are suppressed.
- If the corresponding counts measure is suppressed, the age-standardised rate has been suppressed.
Z-score
No suppression applied.
Data quality
Overall, the quality of the data in the NNAPEDCD is sufficient to be published in this report. However, the following limitations of the data should be taken into consideration when data are interpreted.
States and territories are primarily responsible for the quality of the data they provide. However, the AIHW undertakes extensive validations on receipt of data. Potential errors are queried with jurisdictions, and corrections and resubmissions may be made in response to these edit queries. The AIHW does not adjust data to account for possible data errors or missing values, except where stated.
The AIHW takes active steps to improve the consistency of these data over time.
For 2022–23, the NNAPEDCD may not include emergency presentations to hospitals that have emergency departments that are not in scope for the NAPEDC NMDS. The inclusion criteria for emergency departments may exclude some smaller regional public hospitals.
Prior to 2020–21, the following jurisdictions have provided data to the NNAPEDCD using the NAPEDC National Best Endeavours Data Set (NBEDS) specification:
- Queensland (from 2015–16 to 2019–20);
- Victoria and Western Australia (from 2016–17 to 2019–20).
All other states and territories used the NAPEDC NMDS. The data provided using the NAPEDC NBEDS may not be entirely comparable with data provided using the NAPEDC NMDS.
Although there are national standards for data on non-admitted patient emergency department services, the way those services are defined and counted varies across states and territories, and over time.
Please also refer to the interactive timeline in Figure 1 of these technical notes for details of changes in ED data over time.
Missing or invalid data
In some cases, the data provided may include missing values (for example, the date/time of physical departure was not recorded), or invalid values (for example, if the time of physical departure was recorded as occurring before the time of presentation).