Casemix classification and health care of the elderly.

The Australian national diagnosis-related groups (AN-DRGs) patient classification has highlighted the distinction between different categories of inpatient care and ambulatory care, and the need for an explicit definition of boundaries of associated categories. A nationally consistent definition of these patient care categories, and of episodes of care according to illness acuity, will facilitate the design of additional casemix classifications to supplement AN-DRGs. Specific features of the AN-DRGs classification will have a major impact on health care of the elderly through incentives created by funding arrangements based on this classification. The use of age as an AN-DRG classification criterion, as a surrogate for definitive secondary diagnoses, should be regarded as an interim measure pending improvement in medical record documentation, further analysis of the relationship of age partitions to these secondary diagnoses, and ongoing improvement of AN-DRG design. The complex process of development of casemix classifications for subacute and ambulatory care has commenced, and will also have a profound impact on health care of the elderly and on all specialities concerned with both acute and chronic illness, again because of financial incentives in the classification design. Funding for development and refinement of each of these casemix classifications will be required if the anticipated benefits are to occur.