Hospital admission data
Hospital admission unit record data are annually extracted from the Victorian Admitted Episodes Dataset (VAED) and supplied to VISU by the Victorian Agency for Health Information (VAHI) at the Victorian Department of Health (DH).
ICD-10-AM was originally developed by the National Centre for Classification in Health (NCCH) in Sydney with assistance from clinicians and clinical coders to ensure that the classification is current and appropriate for Australian clinical practice. The Australian Modifications of ICD-10 are generally updated every two years. The external causes chapters of ICD-10-AM describe the causes of injury, poisoning and adverse events (complications of medical and surgical care).
Injury records are identified by VISU as those with an ICD-10-AM injury code (S00-T98) or external cause code (U50-U73, U90, V00-Y98) in any one of the 40 diagnosis codes recorded in the VAED. However, adverse events and sequelae (late effects) of external causes of morbidity and mortality (Y40-Y89) are usually not included in VISU reports.
The VAED data items held by VISU include:
- Age, gender, postcode, suburb and local government area of residence
- Country of birth
- Date of admission, date of separation (discharge), length of hospital stay (in days), and Same day separation.
- Separation type (patient destination on discharge from hospital): separation and transfer to acute hospital /extended care, death, separation to private residence,/accommodation, separation and transfer to aged care residential facility, separation and transfer to mental health residential facility etc.
Injury surveillance items
Up to 40 codes from any or all of the ICD-10-AM chapters can currently be assigned to each record. These codes are then used to derive the following injury surveillance variables that are added to the VISU-VAED dataset.
- Cause of injury – transport, fall, poisoning etc. [Coded to ICD-10-AM Chapter 20: External Causes of Morbidity and Mortality (V00-Y34)]
- Place of occurrence i.e. location of injury - home, road, street or highway etc. [Coded to ICD-10-AM Chapter 20: External Causes of Morbidity and Mortality (Y92.0-Y92.9)]
- Activity when injured - sports, leisure, work etc. [Coded to ICD10-AM Chapter 20: External Causes of Morbidity and Mortality (U50-U73)]
- Human intent – unintentional; intentional-assault, neglect, self harm; undetermined intent. Intent information is derived from the external cause of injury code.
- Injury diagnosis i.e. exact injury code – superficial injury of scalp, fracture of neck of femur etc. [Coded to ICD-10-AM Chapter 19: Injury, Poisoning and Consequences of External Cause S00-T98]
- Body region injured – head, thorax, shoulder, upper arm etc. Body region information is derived from the injury diagnosis variables.
- Nature of main injury - open wound, fracture, dislocation/ sprain/strain etc. Nature of main injury is derived from the injury diagnosis variables.
Data are currently coded to the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM).
The VAED dataset held at VISU contains only cases where an injury or an external cause of injury is coded for the patient. The external causes chapters of ICD-10-AM describe the causes of injury, poisoning and adverse events (complications of medical and surgical care). The Injury Atlas tables and maps are limited to cases with unintentional injury (external cause code in the range “V00-X59”), and community injury (occurring in settings such as car crashes, sporting and recreational activities and work, i.e., ICD-10-AM codes “S00-T75” and “T79”) in the VAED as the principle diagnosis, and exclude complications of medical and surgical care.
Each record in the dataset represents an episode of care, and not necessarily one incident. A patient may be transferred between and within hospitals for various episodes of care relating to injuries arising from one or more incidents and may therefore be represented by more than one record in the VAED. Admissions as a result of transfer from another hospital or due to a statistical separation from the same hospital are excluded in the Injury Atlas.
Multiple admissions for day-treatments (admitted and separated on the same day) can be recorded for certain patients for the same condition(s): e.g., hyperbaric chamber treatment. When such cases can be clearly identified the relevant readmission records are also excluded from the Injury Atlas.
Sports injury cases are those with an ICD-10-AM activity code of “U50-U71”.
In July 2012 the Victorian Hospital Admission Policy changed significantly so that episodes of care delivered entirely within a designated emergency department or urgent care centre could no longer be categorised as an admission regardless of the amount of time spent in the hospital. Previously, these types of episodes could be categorised as an admission if the length of time in the hospital was four hours or more. This has reduced the number of admissions recorded on the VAED from 2012/13 onwards.