Measuring casemix, severity, and complexity in geriatric patients undergoing rehabilitation.

Geriatric rehabilitation is intended to maintain or restore function, maximize life satisfaction, enhance psychologic well-being, and maintain the social status of older persons. For clinical services to operate efficiently and equitably, payment must be based on rules that are clinically sound and thus reinforce the objectives of the services provided. This article presents a theoretical basis for casemix measurement in medical rehabilitation, contrasts structure of the functional independence measure-function-related groups (FIM-FRGs) intended for casemix measurement to the diagnosis-related groups (DRGs) and resource utilization groups (RUG) III systems designed for acute and long-term care settings, focuses on special issues of relevance to the rehabilitation of older persons, and provides four challenges in an effort to stimulate discussion.