Australian refined diagnosis-related groups (AR-DRG) data cubes

The source of these data is the AIHW National Hospital Morbidity Database. Other data on the principal diagnoses and DRGs of hospitalised patients is available in  Australian Hospital Statistics 2007-08  and  Mental Health Services in Australia 2007-08. Some data have been revised since previously published. For confidentiality, some data have been suppressed.

The AR-DRG cubes for 1997-98 to 2009-10

Australian Refined Diagnosis Related Groups (AR-DRGs) is an Australian admitted patient classification system which provides a clinically meaningful way of relating the number and type of patients treated in a hospital (that is, it's casemix) to the resources required by the hospital. Each AR-DRG represents a class of patients with similar clinical conditions requiring similar hospital services. The classification categorises acute admitted patient episodes of care into groups with similar conditions and similar usage of hospital resources, using information in the hospital morbidity record such as the diagnoses, procedures and demographic characteristics of the patient. For further information regarding AR-DRG's refer to the Department of Health and Ageing website: http://www.health.gov.../casemix-ardrg1.htm

Three data cubes are available on the AR-DRG of the patient. These contain information for:

• 1997-98 to 2004-05, classified using AR-DRG Version 4.0/4.1/4.2
• 1998-99 to 2007-08, classified using AR-DRG Version 5.0/5.1
• 2008-09 to 2009-10, classified using AR-DRG Version 5.1

The variables in the data cube are:

• Year (1997-98, 1998-99, 1999-00, 2000-01, 2001-02, 2002-03, 2004-05, 2006-07, 2007-08)
• Sex (Male, Female, Other/Not reported)
• Age group (5 year groupings, i.e. <1, 1-4, 5-9, 10-14, ... 85+, Not reported)
• Same day flag (Same day/Overnight)
• AR-DRG (Department of Health and Ageing website)

The measures (values) in the data cube are:

• Total separations
• Patient days
• Average length of stay (ALOS)

The AR-DRG data cubes contain separations for which the care type was specifically reported as Acute, Newborn (for separations with at least one qualified day) or was not reported (see Definitions). Where identifiable, other separation care types have been excluded.

Users can view the AR-DRG by using a pull-down menu and can work down from the major diagnostic category (MDC) level to the surgical/medical/other partition of the MDC to the individual DRGs, as outlined below.

• Major diagnostic category
  • Surgical/Medical/Other partition
    • AR-DRG

For example

• MDC 04. Diseases and disorders of the respiratory system
  • Surgical
    • DRG E61A Pulmonary embolism with catastrophic or severe complication or comorbidity

Users of the data cube are likely to require some familiarity with AR-DRGs and have access to the definitions manual. This data access system does not allow searching on key words for AR-DRG. Users will generally need to know what MDC the information they are looking for is in, to work down to more specific levels of detail.

Australian Refined Diagnosis Related Groups (AR-DRGs)

The AR-DRG classification is separated into 23 Major Diagnostic Categories (MDCs) and further categorised into medical, surgical and other groupings. AR-DRG assignment is also influenced by procedures, medical conditions and other factors that differentiate processes of care. Further information regarding the processes involved in AR-DRG assignment is made available by the Department of Health and Ageing at:
http://www.health.gov.../casemix-ardrg1.htm

AR-DRG Versions 4.0, 4.1, 4.2, 5.0, and 5.1

AR-DRG version 4.0, 4.1, 4.2, 5.0, 5.1 and 5.2 was developed by the Department of Health and Ageing. Updates are made to AR-DRG versions to remain in line with continual changes to medical, surgical and ICD-AM coding systems.

Information on ICD-AM classification systems can be found at the National Centre for Classification in Health (NCCH):
http://nis-web.fhs.usyd.edu.au/ncch_new/

Specific details of AR-DRG version modifications and recommendations can be found at:
http://www.health.gov.au.../casemix-ardrg1.htm

All AR-DRG logic and definition changes required the mapping of ICD-9-AM and ICD-10AM diagnosis and procedure codes. 'Mapping' refers to the process of finding an 'equivalent' code between two classifications to enable data users to interpret data partly classified in one classification and partly classified in another. This means that the data will not be completely comparable between years. Caution should therefore be exercised in comparing data between years.

Confidentiality

In order to maintain confidentiality in relation to private hospital activity, some data have been suppressed. This has been applied at:

• the three-digit/character level for the principal diagnosis data cubes,
• at the procedure code level and the block level for the procedures data cubes and
• at the DRG level for the Diagnosis Related Groups data cubes.

Data have been suppressed for a particular diagnosis/procedure/block or Diagnosis Related Group if:

• there are fewer than three reporting units (hospitals or states/territories where the hospitals are not individually identified), or
• there are three reporting units and one contributed more than 85% of the total separations, or
• there are three or more reporting units and two contributed more than 90% of the total separations.

Data for the suppressed categories will not appear in the data cubes, but will be included in the sub-chapter, chapter and grand totals. Thus, the sum of separation counts presented within a chapter or sub-chapter for some codes may not match the total.

Categories suppressed for the Diagnosis Related Groups data cubes 

Data for the suppressed DRGs will not appear in the AR-DRG cubes, but will be included in the MDC totals. Thus, the sum of separation counts for some DRGs may not match the total.

A list of the suppressed categories can be found in Suppressed categories for DRG cubes (14KB XLS). 

Categories suppressed for the Principal diagnosis data cubes 

Data for the suppressed three-digit categories will not appear in the principal diagnosis cubes, but will be included in the sub-chapter and chapter totals. Thus, the sum of separation counts for some three-digit/character codes may not match the total.

A list of the suppressed categories can be found in Suppressed categories for principal diagnosis cubes (28KB XLS). 

Categories suppressed for the Procedures data cubes 

Data for the suppressed categories will not appear in the procedure cubes, but will be included in the upper level totals. That is, data for the suppressed procedure codes will be included in the block, sub-chapter and chapter totals, and data for the suppressed blocks will be included in the sub-chapter and chapter totals. Thus, the sum of procedure counts for some blocks, sub-chapters or chapters may not match the total.

A list of the suppressed categories can be found in Suppressed categories for procedure cubes (681KB XLS).

Links to Principal Diagnosis and Procedures data cubes

• Principal Diagnosis data cubes
• Procedures data cubes