Development of an Episode of Illness Classification for Population Management Using Pharmacy Data

Abstract

The purpose of this study is to develop an episode of illness case mix system using pharmaceutical data. The objective was the development of a categorical episode of illness classification system using a database with linked inpatient, outpatient, and pharmaceutical data, using a claims database of 300,000 enrollees. An episode of illness classification system was developed using pharmaceutical data (CRxGs or Clinical Pharmaceutical Groups) based on an already existing system (Clinical Risk Groups or CRGs, which uses diagnoses and procedures). CRxGs with its categorical model can link individual medications, combinations of medications, and factors such as the duration of treatment to specific diseases. It also differentiates the severity of those diseases. This identification can be used to identify individuals who might benefit from more aggressive case management and to manage populations of patients with a particular disease. Episodes of illness are key to effective population management. The name and dosage of the pharmaceutical add important information to our understanding of how to measure episodes of illness.