Data source and key concepts

National Hospital Morbidity Database

The National Hospital Morbidity Database (NHMD) is a compilation of episode-level records from admitted patient morbidity data collections in Australian hospitals. It includes demographic, administrative and length of stay data for each hospital separation. Clinical information such as diagnoses, procedures undergone and external causes of injury and poisoning are also recorded. For further details on the scope and quality of data in the NHMD, refer to the data quality statements.

Further information on admitted patient care for the 2018–19 reporting period can be found in the report Admitted patient care 2018–19: Australian hospital statistics (AIHW 2019). The 2018–19 collection contains data for hospital separations that occurred between 1 July 2018 and 30 June 2019. Admitted patient episodes of care/separations that began before 1 July 2018 are included if the separation date fell within the collection period (2018–19). A record is generated for each separation rather than each patient. Therefore, those patients who separated from hospital more than once in the reference year have more than one record in the database.

Specialised mental health care is identified by the patient having one or more psychiatric care days recorded—that is, care was received in a specialised psychiatric unit or ward during that separation. In public acute hospitals, a ‘specialised’ episode of care or separation may comprise some psychiatric care days and some days in general care. An episode of care from a public psychiatric hospital is deemed to comprise psychiatric care days only and to be ‘specialised’, unless some care was given in a unit other than a psychiatric unit, such as a drug and alcohol unit.

Although there are national standards for data on admitted patient care, the results presented here may be affected by variations in admission and reporting practices between states and territories. Interpretation of the differences between states and territories therefore needs to be made with care. The principal diagnosis refers to the diagnosis established after observation by medical staff to be chiefly responsible for the patient’s episode of admitted patient care. For 2018–19, diagnoses are classified according to the International Statistical Classification of Diseases and Related Health Problems, 10th revision, Australian Modification (ICD-10-AM 10th edition) (ACCD 2016). Further information on this is included in the technical information section.

For 2018–19, procedures are classified according to the Australian Classification of Health Interventions, 10th edition. Further information on this classification is included in the technical information section. More than one procedure can be reported for a separation and not all separations have a procedure reported.

Private Hospitals Association Private Psychiatric Hospitals Data Reporting and Analysis Service

The Australian Private Hospitals Association Private Psychiatric Hospitals Data Reporting and Analysis Service (PPHDRAS), previously known as the Private Mental Health Alliance Centralised Data Management Service (PMHA CDMS), was launched in Australia in 2001 to support private hospitals with psychiatric beds to routinely collect and report on a nationally agreed suite of clinical measures and related data for the purposes of monitoring, evaluating and improving the quality of and effectiveness of care. The PPHDRAS works closely with private hospitals, health insurers and other funders (e.g. Department of Veterans’ Affairs) to provide a detailed quarterly statistical reporting service on participating hospitals’ service provision and patient outcomes.

The PPHDRAS fulfils two main objectives. Firstly, it assists participating private hospitals with implementation of their National Model for the Collection and Analysis of a Minimum Data Set with Outcome Measures. Secondly, the PPHDRAS provides hospitals and private health funds with a data management service that routinely prepares and distributes standard reports to assist them in the monitoring and evaluation of health care quality. The PPHDRAS also maintains training resources for hospitals and a database application which enables hospitals to submit de-identified data to the PPHDRAS. The PPHDRAS produces an annual statistical report. In 2018–19, the PPHDRAS accounted for 96% of all private psychiatric beds in Australia (APHA 2020).

The classification of diagnostic groups used by the PPHDRAS is based on the ICD-10 principal diagnosis assigned to the episode of care at discharge.

There are 8 clinical groupings of the ICD-10 diagnoses relating to mental and behavioural disorders, they are as follows:

  • Schizophrenia, Schizoaffective and Other Psychotic Disorders. This group includes ICD-10 diagnoses of: Psychotic disorders due to psychoactive substance use (F1x.5 and F1x.7), Schizophrenia (F20), Schizotypal disorders (F21), Delusional disorders (F22 and F24), Acute and transient psychotic disorders (F23), Schizoaffective disorders (F25), and Other nonorganic psychotic disorders (F28 and F29).
  • Major Affective and Other Mood Disorders. This group includes ICD-10 diagnoses of Manic episodes and bipolar affective disorders with current episode manic (F30, F31.0, F31.1 and F31.2), Depressive episodes, bipolar disorders with current episode depressed or mixed, and Recurrent depressive disorders (F31.3, F31.4, F31.5, F31.6, F31.7, F31.8, F31.9, F32 and F33), and Persistent mood disorders including cyclothymia and dysthymia, and Other mood disorders (F34, F38 and F39).
  • Post Traumatic and Other Stress-related Disorders. This group includes ICD-10 diagnoses of Reactions to severe stress including acute stress reactions (F43.0, F43.8 and F43.9), Adjustment disorders with brief depressive reactions (F43.20), Adjustment disorders with prolonged depressive reactions (F43.21), Other adjustment disorders (F43.22 and F43.28) and Posttraumatic stress disorders (F43.1).
  • Anxiety Disorders. This group includes ICD-10 diagnoses of Anxiety disorders including phobic anxiety, Panic disorder, Generalised anxiety disorder and Other neurotic disorders (F40, F41 and F48), and Dissociative disorders (F44). It does not include Obsessive Compulsive Disorders (F42) or Somatoform Disorders (F45) which are classified elsewhere.
  • Alcohol and Other Substance Use Disorders. This group includes ICD-10 diagnoses of Alcohol and Other psychoactive substance intoxication, harmful, use, dependence and withdrawal (F1x.0, F1x.1, F1x.2, F1x.3, F1x.4, F1x.8 and F1x.9).
  • Eating Disorders. This group includes ICD-10 diagnoses of Anorexia nervosa and Atypical anorexia nervosa (F50.0 and F50.1), and Eating disorders other than anorexia nervosa (F50.2, F50.3, F50.4- and F50.9).
  • Personality Disorders. This group includes ICD-10 diagnoses of Paranoid and schizoid personality disorders (F60.0 and F60.1), Dissocial personality disorders including antisocial personality disorder (F60.2), Emotionally unstable personality disorders (includes borderline and impulsive) (F60.3), Histrionic, Anankastic (obsessive-compulsive), Anxious, and Dependent personality disorders (F60.4, F60.5, F60.6 and F60.7), and Other personality disorders (F60.8, F60.9, F61.0, F61.1, F62, F63, F68 and F69).
  • Other Disorders, Not Elsewhere Classified. This group includes all remaining psychiatric and other diagnoses including: Organic Disorders (F00 through F09 and F1x.6); Obsessive Compulsive Disorders (F42); Somatoform disorders (F45); Behavioural Syndromes Associated with Physiological Disturbances and Physical Factors (F51, F53, F54, and F59); Sexual Disorders (F52, F64, F65 and F66); Mental Retardation (F70, F71, F72, F73, F78 and F79); Disorders of Psychological Development (F80, F81, F82, F83, F84, F88 and F89); Disorders of Childhood and Adolescence (F90, F91, F92, F93, F94, F95 and F98.0); Other Disorders, including ICD-10 diagnoses of Mental disorders, not otherwise specified (F99) and all other valid non-psychiatric diagnoses (i.e., diagnoses not grouped under either MDC 19 or MDC 20 in AR-DRG 4).

The classification of patients into urban versus non-urban groups was based on the ASGC Remoteness classification of the Postcode of their Area of usual residence, at the first day of care within the financial year. In cases whether the Area of usual residence was missing from that first day’s record, the first valid value for the patient is used. Patients, whose Area of usual residence was in ASGC group Major cities were classified as “Urban”, whilst those in the remaining groups (Inner regional, Outer regional, Remote and Very remote) were classified as “Non-urban”.

Statistics for States and Territories were aggregated in accordance with PPHDRAS policy which, in order to ensure the privacy and confidentiality of both patients and providers, prohibits individual State or Territory statistics being reported in cases where the number of Hospitals is less than 5. As a consequence, statistics for the Australian Capital Territory are aggregated with those for New South Wales; whilst those for South Australia, Western Australia, Tasmania and Northern Territory are also aggregated.

Key concepts - Same day admitted mental health-related care
Key concept Description
Diagnostic group The classification of diagnostic groups is based on the ICD-10 principal diagnosis assigned to the episode of care at discharge. There are 8 clinical groupings of the ICD-10 diagnoses relating to mental and behavioural disorders. Further details of these diagnostic groups, can be found in the data source section.
Episode An episode of care in Private hospitals involves a period of care from admission to separation. Counts of episodes include only clinically substantive episodes of care. Episodes that are of brief duration (1 or 2 contacts only) and episodes during which contacts were sparse (average interval between contacts 6 weeks or greater) are excluded from the count. Consequently, the count of episodes can in some cases be less than the count of unique patients.
Mental health-related

A separation is classified as mental health-related if:

  • it had a mental health-related principal diagnosis which, for admitted patient care, is defined as a principal diagnosis that is either a diagnosis that falls within the section on Mental and behavioural disorders (Chapter 5) in the International Statistical Classification of Diseases and Related Health Problems, 10th revision, Australian Modification (ICD-10-AM) classification (codes F00–F99) or a number of other selected diagnoses (the Classification codes section has the full list of applicable diagnoses), or
  • it included any specialised psychiatric care.
Principal diagnosis The principal diagnosis is the diagnosis established after study to be chiefly responsible for occasioning the patient’s episode of admitted patient care.
Procedure Procedure refers to a clinical intervention that is surgical in nature, carries an anaesthetic risk, requires specialised training and/or requires special facilities or services available only in an acute care setting. Procedures therefore encompass surgical procedures and non-surgical investigative and therapeutic procedures, such as X-rays. Patient support interventions that are neither investigative nor therapeutic (such as anaesthesia) are also included.
Same day admitted mental health care

The definition of same day admitted mental health care is slightly different between the two data sources.

A separation for Public hospitals is classified as same day admitted mental health care if the following apply:

  • the separation was a same day separation (that is, admission and separation occurred on the same day),

An admission for Private hospitals is classified as same day admitted mental health care based on data reported as ‘Same day episode’ including:

  • Hospital-based same day admissions,
  • Single overnight for same day admissions for ECT,
  • Hospital-in-the-home or outreach care visits to patient’s homes recorded as same day admissions.
Separation Separation is the term used to refer to the episode of admitted patient care, which can be a total hospital stay (from admission to discharge, transfer or death) or a portion of a hospital stay beginning or ending in a change of type of care (for example, from acute care to rehabilitation). 'Separation' also means the process by which an admitted patient completes an episode of care by being discharged, dying, transferring to another hospital or changing type of care. Each record includes information on patient length of stay. A same-day separation occurs when a patient is admitted and separated from the hospital on the same date. An overnight separation occurs when a patient is admitted to and separated from the hospital on different dates. 
Specialised psychiatric care A separation is classified as having specialised psychiatric care if the patient was reported as having spent 1 or more days in a specialised psychiatric unit or ward. 
Without specialised psychiatric care A separation is classified as without specialised psychiatric care if the patient did not receive any days of care in a specialised psychiatric unit or ward. Despite this, these separations are classified as mental health related because the reported principal diagnosis for the separation is either one that falls within the Mental and behavioural disorders chapter (Chapter 5) in the ICD-10-AM classification (codes F00–F99) or is one of a number of other selected diagnoses  (technical information).