Functional status outcomes in rehabilitation. Implications for prospective payment

Previous studies have demonstrated that functional status is a significant predictor of resource utilization for rehabilitation patients. Before implementing a prospective payment system (PPS) for rehabilitation, it is important to first: 1) develop an underlying conceptual framework of rehabilitation resource use; and 2) understand how the role of functional status may vary by rehabilitation condition. In this study, a theoretical model of rehabilitation is presented that proposes relationships between patient and provider characteristics, rehabilitation treatment, costs, and clinical outcomes of rehabilitation. Also presented are regression analyses based on this model for a key outcome of rehabilitation, change in functional status, for nine rehabilitation conditions using variables that minimize adverse incentives by providers in selecting patients for admission to rehabilitation. The change-in-functional-status model explained the most variance for back injury, cardiopulmonary, and arthritis, and less variance for stroke, spinal cord injury, and neurologic impairment. The significant predictors of change in functional status varied by condition. Results support the use of functional status measurements in a PPS for rehabilitation services, the need to refine the measurement of functional status, and the use of condition-specific activities of daily living (ADL) items to include in summary indices.