Patient case mix measurement using outpatient drug dispense data.

This article outlines issues concerned with the development of case mix measurement using outpatient drug dispense databases, particularly as this method is being explored at Kaiser Permanente. Development is oriented to a population-based measure that emphasizes identification of major chronic diseases, such as diabetes, heart disease, hypertension, and asthma. Examples illustrate potential applications in the areas of utilization management and resource allocation. Questions concerning the integrity of this method--that is, how reliably the method represents population morbidity--are addressed.