Principal Diagnosis data cubes

  • Web report
  • Last updated: 17 May 2017
  • Author: AIHW
 

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. In some cases, the principal diagnosis is described in terms of a treatment for an ongoing condition (for example, same-day care for dialysis).

User guide

Hospital data cubes user guide

The data cubes can be used to explore a range of clinical data related to hospital separations. This document will give you some tips on how to expand out clinical categories to finer detail, add other breakdowns, and also how to download the data to an Excel file.

Expanding categories and sub-categories

Clicking on the plus (+) symbols against each row will expand that item into its relevant sub categories, within the current view.

Clicking the arrow symbols beside the plus will expand the category and also limit the view to just that expanded area of interest.

Right clicking on category headings such as ICD Diagnosis Chapter, ICD Diagnosis sub-chapter etc. will bring up a menu where you can click ‘Expand All’, which will expand every item in that list. If you also do this with the subchapter headings you can expand out the entire data cube and display all of the available information.

Screenshot of data cubes: Expanding categories and sub-categories

Adding breakdowns

In the default view, the cube will just present the number of hospital separations by year but you can also add other breakdowns such as by Age group, sex, and patient days or average length of stay where available from the left hand window pane.

To add an extra breakdown, left click the item from the left hand window pane and drag and drop it over one of the light blue solid lines that appears in the data table to the right. A solid black line with a black arrow appears when the item is in a valid place to be dropped (see image below for example using Age group)

Screenshot of data cubes: Adding breakdowns

Once the variable has been added, you can right-click over it to further manipulate its position or hide it again.

Exporting data to Excel

The current view of the data cube can easily be exported to Excel by choosing ‘Export…’ from the ‘File’ menu, and then saving the zipped file to your computer. When extracting the zip archive you will need to extract all files in the archive before opening the downloaded Excel document.

Exporting the whole data cube

To do this, first see the notes about Expanding the categories and sub categories first and using Expand All. Then once you have the full view of the cube, export the data as per the step above.

More details on each data cube

The following sections cover some basic information on how the different classifications break down into finer detail within each of the three data cubes.

There are three data cubes covered in the following sections:

Tips on using the AR-DRGs data cube

Data cubes will open in a new window.

The use of the different editions in the data cubes means that data across years may not be exactly comparable.

The variables in the data cube are:

  • Year
  • 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

The measures (values) in the data cube are:

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

Within the cubes, 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
      • AR-DRG E01A Major chest procedures with catastrophic 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. More information about the breakdowns and categories used within the data cube are given below.

Major diagnostic categories (MDCs)

The data cube is categorised by the 23 Major Diagnostic Categories (MDCs) into which the patient’s diagnosis and the associated AR-DRG falls. They correspond generally to the major organ systems of the body. Below is a list of each of the 23 MDCs and the range of AR-DRGs that fall into each category.

Major Diagnostic Categories and the AR-DRG ranges covered by each

MDC

MDC Description

AR-DRGs
beginning with

 

Pre-MDC

Major procedures where the principal diagnosis may be associated with any MDC

A

01.

Diseases and disorders of the nervous system

B

02.

Diseases and disorders of the eye

C

03.

Diseases and disorders of the ear, nose, mouth and throat

D

04.

Diseases and disorders of the respiratory system

E

05.

Diseases and disorders of the circulatory system

F

06.

Diseases and disorders of the digestive system

G

07.

Diseases and disorders of the hepatobiliary system and pancreas

H

08.

Diseases and disorders of the musculoskeletal system and connective tissue

I

09.

Diseases and disorders of the skin, subcutaneous tissue and breast

J

10.

Endocrine, nutritional and metabolic diseases and disorders

K

11.

Diseases and disorders of the kidney and urinary tract

L

12.

Diseases and disorders of the male reproductive system

M

13.

Diseases and disorders of the female reproductive system

N

14.

Pregnancy, childbirth and the puerperium

O

15.

Newborns and other neonates

P

16.

Diseases and disorders of the blood and blood forming organs and immunological disorders

Q

17.

Neoplastic disorders (haematological and solid neoplasms)

R

18.

Infectious and parasitic diseases

S-T

19.

Mental diseases and disorders

U

20.

Alcohol/drug use and alcohol/drug induced organic mental disorders

V

21.

Injuries, poisoning and toxic effects of drugs

W-X

22.

Burns

Y

23.

Factors influencing health status and other contacts with health services

Z

Error-DRG

Error DRGs

8-9

Broad categories of service

The data cube is next broken down by the surgical, medical, and other partitions of the AR-DRG. These partitions represent the broad category of service associated with that AR-DRG, as described below:

  • Surgical: separations for which the AR-DRG belonged to the Surgical partition of the AR-DRG classification (involving an operating room procedure).
  • Medical: separations for which the AR-DRG belonged to the Medical partition (not involving an operating room procedure).
  • Other: separations for which the AR-DRG did not belong to the Surgical or Medical partitions (involving a non-operating room procedure, such as endoscopy).

Tips on using the Principal diagnosis data cube

Data cubes will open in a new window.

The use of the different ICD editions in the data cubes means that data across years may not be exactly comparable.

The variables in the data cubes are:

  • Year
  • 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/non-same day)
  • Principal diagnosis

The measures (values) in the data cubes are:

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

Within the cubes, users can view the diagnoses by using a pull-down menu and can work down from the broad chapter level in the ICD classifications to more specific categories (i.e. principal diagnosis code), as illustrated below:

  • ICD Chapter
  • ICD Sub-Chapter
  • ICD 3-character code
  • ICD 4-character code (where relevant)
  • ICD 5-character code (where relevant)

For example:

  • Endocrine, nutritional and metabolic diseases (E00-E89)
    • Disorders of thyroid gland (E00-E07)
      • Other hypothyroidism (E03)
        • Atrophy of thyroid (acquired) (E03.4)

Users of the data cubes are likely to require some familiarity with ICD-9-CM and ICD-10-AM and can also refer to the Australian Hospital Statistics publications. This data access system does not allow searching on keywords 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. 

International Classification of Diseases (ICD)

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 data cubes means that data from 1998–99 onwards may not be exactly comparable with the earlier data (1993-94 to 1997-98).

In addition, there are some differences in the coding between ICD-10-AM editions and these will be reflected in the cube. Readers should refer to further information below for information on how to access the full classification and for detailed information on the differences between ICD-9-CM, ICD-10-AM and the different editions of ICD-10-AM.

The following is a list of the ICD disease chapters used in the data cube and the code ranges covered by each:

Chapter

Disease classification

Diagnoses
within range

1

Certain infectious and parasitic diseases

A00–B99

2

Neoplasms

C00–D48

3

Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism

D50–D99

4

Endocrine, nutritional and metabolic diseases

E00–E99

5

Mental and behavioural disorders

F00–F99

6

Diseases of the nervous system

G00–G99

7

Diseases of the eye and adnexa

H00–H59

8

Diseases of the ear and mastoid process

H60–H99

9

Diseases of the circulatory system

I00–I99

10

Diseases of the respiratory system

J00–J99

11

Diseases of the digestive system

K00–K99

12

Diseases of the skin and subcutaneous tissue

L00–L99

13

Diseases of the musculoskeletal system and connective tissue

M00–M99

14

Diseases of the genitourinary system

N00–N99

15

Pregnancy, childbirth and the puerperium

O00–O99

16

Certain conditions originating in the perinatal period

P00–P99

17

Congenital malformations, deformations and chromosomal abnormalities

Q00–Q99

18

Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified

R00–R99

19

Injury, poisoning and certain other consequences of external causes

S00–T99

21

Factors influencing health status and contact with health services

Z00–Z99

Tips on using the Procedures data cube

Data cubes will open in a new window.

The use of the different editions in the data cubes means that data across years may not be exactly comparable.

One or more procedures can be reported for each separation in the National Hospital Morbidity Database, but procedures are not undertaken for all hospital admissions, and so only a proportion of the separation records include procedure data.

The variables in the data cubes are:

  • Year
  • 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 or Overnight)
  • Procedure

The measures (values) in the data cubes are:

  • Total procedures

Within the cubes, users can view the procedures by using a pull-down menu and can work down from the broad chapter level in the ACHI classifications to more specific categories (i.e. procedure code), as illustrated below.

  • ACHI Chapter
    • ACHI Sub-Chapter
      • ACHI Block number
        • ACHI Procedure code

For example:

  • 7. Procedures on Respiratory System (Blocks 520-569)
    • Lung and Pleura (Blocks 548-558)
      • Block 549 Incision procedures on lung or pleura
        • 38415-00 Incision of pleura 

Users of the data cubes are likely to require some familiarity with the Australian Classification of Health Interventions (ACHI) and have access to the full publications. This data access system does not allow searching on key words or ACHI 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.

Australian Classification of Health Interventions

The Australian Classification of Health Interventions (ACHI) is the Australian national standard for procedure and intervention coding in Australian hospitals, based around the Medicare Benefits Schedule (MBS). Guidelines for the use of ACHI are contained in the Australian Coding Standards (ACS).

There are some differences in the coding between editions and these will be reflected in the cube. Readers should refer to the further information section below for information on how to access the full classification and for detailed information on the differences between ACHI editions.

ACHI has been structured with a principal axis of anatomical site. Within each chapter the anatomical site has been structured by a 'head-to-toe' approach. The secondary axis is procedure type, beginning with the least invasive procedure through to the most invasive procedure. Due to the historical development of ACHI, code numbers do not always appear in numerical order within the tabular list. A third level axis, called a block, has been introduced. Blocks are numbered sequentially in the tabular list to assist clinical coders in locating a specific code and have titles that relate specifically to the codes within the block. There are certain chapters that are an exception to the general format: Dental services, Obstetric procedures, Radiation oncology procedures, Noninvasive, cognitive and other interventions, not classified elsewhere and Imaging services.

The following is a list of the ACHI procedure chapters and the code ranges covered by each:

Chapter

Procedure chapter description

Block range

1.

Procedures on Nervous System

1-86

2.

Procedures on Endocrine System

110-129

3.

Procedures on Eye and Adnexa

160-256

4.

Procedures on Ear and Mastoid Process

300-333

5.

Procedures on Nose, Mouth and Pharynx

370-422

6.

Dental Services

450-490

7.

Procedures on Respiratory System

520-571

8.

Procedures on Cardiovascular System

600-777

9.

Procedures on Blood and Blood-Forming Organs

800-817

10.

Procedure on Digestive System

850-1011

11.

Procedures on Urinary System

1040-1129

12.

Procedures on Male Genital Organs

1160-1203

13.

Gynaecological Procedures

1240-1299

14.

Obstetric Procedures

1330-1347

15.

Procedures on Musculoskeletal System

1360-1580

16.

Dermatological and Plastic Procedures

1600-1718

17.

Procedures on Breast

1740-1759

18

Radiation Oncology Procedures

1786-1800

19.

Non-invasive, Cognitive and Other Interventions, not elsewhere classified

1820-1922

20.

Imaging Services

1940-2016

Block numbers and procedure codes can vary across editions, with the same block numbers representing two different procedure groups. This should be taken into consideration when comparing data using different ACHI editions. Separate cubes exist for each of the ICD-10-AM/ACHI editions as it is difficult to map across editions.