Classifications

This page contains general information about Casemix classifications, diagnosis related groups, and Australian refined diagnosis related groups.

Casemix classification

The term “Casemix” refers to the type or mix of patients treated by a hospital or unit. Casemix based funding is one of the key funding models currently used in Australian health care services for reimbursement of the cost of patient care. Casemix was developed for in-patient use, but some states and territories have developed Casemix funding models for outpatient and ambulatory care settings.

Diagnosis Related Groups

Diagnosis Related Groups (DRGs) are the best-known classification system used in this funding model. It classifies acute inpatient episodes into categories based on clinical content and resource consumption. The purpose of DRGs is to relate a hospital’s casemix to resource demands and associated costs experienced by the hospital. Therefore a hospital having a more complex casemix from a DRG perspective means that the hospital treats patients who require more resources. It does not necessarily mean that the hospital treats patients with a greater severity of illness, a greater treatment difficulty, a poorer prognosis or a greater need for intervention.

A single acute episode of inpatient care is allocated to one DRG using coded clinical information derived from the patient’s medical record. The coding classification system includes the International Statistical Classification of Diseases and Health Related Problems -10-Australian Modification (ICD-10-AM), Australian Classification of Health Interventions (ACHI), Australian Coding Standards (ACS). This system is developed and maintained by the National Centre for Classification in Health (NCCH) and is updated every two years. The DRG classification is developed and maintained in line with the ICD-10-AM, ACHI, ACS updates. For additional information on NCCH, see the following link: http://nis-web.fhs.usyd.edu.au/ncch%5Fnew/

DRGs enable the measurement of hospital output, thus provide a basis for funding, budgeting and charging. In addition, DRGs can be used for policy development in relation to access and equity issues, analysis of clinical and coding practice, and market assessments of demand for drugs, prostheses, etc.

Australian Refined Diagnosis Related Groups (AR-DRG)

The Australian National Diagnosis Related Groups (AN-DRG) was the first national DRG classification (1992-1997). The Australian Refined Diagnosis Related Groups (AR-DRG) are the second and the current, national DRG classification. This also signified the change in coding system from ICD-9-CM (The International Classification of Diseases, Ninth Revision, Clinical Modification) in AN-DRG to ICD-10-AM (The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification) in AR-DRG.

The refinement of AR-DRG’s is ongoing and follows a two-year cycle. Anyone can submit a proposal to enhance the classification. There are two types of revision: major or minor. Major revisions involve creating new DRGs, changing DRG names or cost weights. Minor revisions include moving a code from one DRG to another, changing a procedure status or changing a complication and comorbidity level of a diagnosis. Top of page