Principal Diagnosis Data Cubes

Principal diagnosis cubes for 1993-94 to 1997-98 and 1998-99 to 2006-07

The principal diagnosis is defined as the diagnosis established after study to be chiefly responsible for occasioning the patient's episode of care in hospital. 

Four interactive data cubes are available on the principal diagnosis of patients seen in Australian hospitals. They contain information for:

• Separation statistics by principal diagnosis in ICD-9-CM, Australia, 1993-94 to 1997-98; 

• Separation statistics by principal diagnosis in ICD-10-AM, Australia, 1998-99 to 2006-07; 

• Separation statistics for mental health-related separations by principal diagnosis in ICD-10-AM, Australia, 2001-02 to 2004-05;

• Separation statistics for separations with specialised psychiatric care by principal diagnosis in ICD-10-AM, Australia, 1998-99 to 2004-05.

Note to data cube users: In order to maintain confidentiality in relation to private hospital activity, some data have been suppressed at the three-digit/character level of the diagnosis classification. 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. For more information on the methodology used for suppression and a complete list of suppressed Principal diagnosis codes see this attachment.

Principal diagnoses are classified according to either the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) or the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM). The use of the different classifications (ICD-9-CM and ICD-10-AM) in the two databases means that data for 1998-99 to 2006-07 may not be exactly comparable with data for 1993-94 to 1997-98.

Users of the data cubes are likely to require some familiarity with ICD-9-CM and ICD-10-AM and have access to the full publications. This data access system does not allow searching on key words or ICD-9-CM/ICD-10-AM codes. Users will generally need to know what chapter the information they are looking for is in, to work down to more specific levels of detail. The ICD-10-AM classification is published by the National Centre for Classification in Health, refer to their website for more detailed information on the classification.

The measures (values) in the data cubes are:

• Total separations

• Patient days

• Psychiatric care days (for specialised psychiatric care only)

• Average length of stay (ALOS)

The variables in the data cubes are:

• Year (1993-94, 1994-95, 1995-96, 1997-98) (1998-99, 1999-00, 2001-02, 2002-03, 2003-04, 2004-05, 2005-06, 2006-07)

• 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 (Same day/Overnight)

•  Mental health legal status (for specialised psychiatric care only)

• Principal diagnosis

Last reviewed by Hospitals Unit on 29 March 2008