Toward an international case mix index for comparisons in OCED countries. Organization for Economic Cooperation and...

During the last 20 years, a number of studies have examined the effect of Diagnosis Related Group (DRG)-based health care prospective payment systems on the cost and quality of services. To examine these issues, it is necessary to control for variations in patient mix and the related resources needed by incorporating some form of a case mix index. As part of our ongoing research on comparative DRG-based health care payment systems, we develop a preliminary, international case mix index using the Organization for Economic Cooperation and Development (OECD) health care database. We illustrate the application of our case mix index and use it to devise a standardized cost per case and a standardized cost per day for several countries. We also provide some preliminary analysis of the data demonstrating the observable and predictable effects of DRG-based payments on case m ix index, length of stay,cost per day, and cost per case.