Outcomes of hospital-onset injury

This section describes differences in the length of stay, intensive care unit (ICU) admission, discharge to residential care and in-hospital mortality for separations with a record of hospital-onset injury compared to those without for 2024–25. It excludes all separations with any diagnosis of T80-T88 Complications of surgical and medical care or T90-T98 Sequelae of injuries, of poisoning and of other external causes, including episodes with a record of other hospital-onset injuries, to minimise the potential for these complications to influence or distort the analysis of injury-related outcomes.

Measuring how hospital-onset injuries affect patient outcomes is difficult due to complex links between patient health, length of stay, and injury risk. Such injuries can lengthen hospitalisation (Hasan et al., 2025; Morello et al., 2015), however patients with longer stays often have more severe illnesses and are at higher risk of injury. Extended hospital stays increase the chance of adverse events (Hauck, 2011). Some research has used specialised methods to assess these effects on patient outcomes (Hauck, 2011; Trentino et al., 2013).

Length of stay

Patients with hospital-onset injuries had a median length of stay that was 11 days longer than those without such injuries, excluding same day separations (Table 3).

Hospital-onset injury rates were highest for patients who took leave days, received hospital in the home care, or had non-acute and sub-acute care (see Health service characteristics).

In all groups, those with hospital-onset injury also stayed longer in the hospital compared to those without injury (Table 3). The greatest differences in median length of stay were seen among patients with leave days (30 days longer), those receiving mental health care (14 days), and those with hospital in the home care (14 days) (Table 3).

While patients without injury in these groups also tended to have longer stays due to more complex care needs, the presence of a hospital-onset injury was associated with an additional increase in length of stay.

This pattern is likely influenced by patient complexity: individuals who are older, have more comorbidities, or higher clinical severity not only have longer hospital stays regardless of injury but are also more likely to experience hospital-onset injuries, which could further extend their stay.

Table 3: Length of stay of separations with and without hospital-onset injuries, by care type, leave days and hospital in the home, 2024–25

Patient group

Hospital-onset injury (median days)

No hospital-onset injury (median days)

Hospital-onset injury (25th–75th percentile)

No hospital-onset injury (25th–75th percentile)

All

13

2

6–27

1–5

Acute care

10

2

5–19

1–5

Rehabilitation care

23

13

14–40

8–20

Palliative care

16

5

8–31

2–10

Other subacute care

29

12

15–53

5–22

Mental health care

24

10

12–47

4–21

Leave days

42

12

22–84

5–26

No leave days

13

2

6–26

1–5

Hospital in the home

20

6

11–38

3–14

No hospital in the home

13

2

6–27

1–5

Notes:

  1. Percentiles express where an observation falls in range of other observations. For example, the 25th percentile indicates that 25% percent of observations are equal to or less than its value.
  2. Excludes diagnosis codes T80-T88 Complications of surgical and medical care and T90-T98 Sequelae of injuries, of poisoning and of other external causes.
  3. Analysis excludes care types 7.3, 9, 10, and all same day separations.
  4. Downloadable data tables are available on Data. See Table S22.

Source: AIHW analysis of the National Hospital Morbidity Database

ICU admission

Separations with a record of hospital-onset injury were 5 times as likely to be admitted to ICU than those without hospital-onset injury.

In 2024–25, 3,914 (7.6%) separations with hospital-onset injury had an ICU stay, compared to 150,946 (1.5%) of separations without hospital-onset injury.

However, the temporal sequence cannot be established, and it is not possible to determine whether the ICU admission occurred before or after injury, or whether the injury occurred during the ICU stay.

Patients requiring ICU admission are acutely unwell and may therefore be at higher risk of hospital-onset injury; conversely, the injury itself may contribute to subsequent ICU admission. The available data do not allow these effects to be distinguished.

Separation mode

Compared to separations with no hospital-onset injury, a higher proportion of hospital-onset injury separations during 2024–25:

  • had a statistical discharge, that is a change in care type – 15% and 2%
  • were discharged or transferred to an acute hospital – 13% and 4%,
  • were discharged or transferred to residential aged care that was not the usual place of residence – 5% and 0.4%
  • died in hospital – 5% and 1% (Figure 13).

For comparisons of all modes of separation for each year, see Data.

Figure 13: Separation mode for separations with and without hospital-onset injuries, 2024–25

Column chart comparing separation modes for cases with and without hospital-onset injuries in 2024-25. Injury cases have notably higher percentages in all categories, with statistical discharge type change at 15%, another acute hospital at 13%, residential aged care and died both at 5%, compared to much lower percentages for no injury cases.

Downloadable data tables are available on Data. See Table S23.

Source: AIHW analysis of the National Hospital Morbidity Database | Data source overview

Previous page
Next page