Case mix use in 25 countries: a migration success but international comparisons failure.

Diagnosis related groups (DRGs) were the first health management tool to group patients in clinical meaningful categories with homogeneous resources consumption. They belong to case mix measures that have been introduced in the USA in the seventies to identify clinical differences in groups of patients as well as to document variation in hospitals and physicians practices by comparing similar groups with each others. They are also used to adjust payment rates and to improve quality of care. This innovative concept migrated from the USA to several Western European countries and to Australia first, to Eastern Europe and Asia soon thereafter. The main objective in most countries concerns a hospital financing new methodology, based on similar groups of patients, by applying a global budget. The main result of this international overview of 25 countries is to show the difficulty to make international comparisons, mainly because of the absence of a universal classification system for procedures. Furthermore, diagnostic classification systems to group patients vary also by country. These obstacles to compare hospital and physician practices have profound roots in cultural differences and in political sensitivity for organising health care delivery between countries. The development of an appropriate Case Mix grouper tool including uniform diagnoses and procedures codes, leading to international use becomes a public health priority.