Development of a Multipurpose Dataset to Evaluate Potential Medication Errors in Ambulatory Settings

Abstract : Ten health maintenance organizations (HMOs) of the HMO Research Network Center for Education and Research on Therapeutics (CERT) participated in a descriptive study of the frequency of potential medication errors in ambulatory settings. This report describes the data development process and demographic information of the study subjects. As this data resource has served as the basis for seven patient safety studies, it is crucial to describe in detail the rationale for this data development scheme and the demographic and membership attrition information of the study population. Approximately 200,000 health plan members who had pharmacy benefits at anytime from January 1, 1999 through June 30 20001, were selected from each of the 10 HMOs. The study population included all of the health plan members in a randomly selected clinical practice of each HMO, resulting in a representative sample of the source population. For each study subject, claims records of drug dispensing, hospitalization, ambulatory visits, and special examinations during the 2.5-year study period were organized in a standard format at each HMO. The source data reside at each HMO, and only de- identified and processed data were combined for final analyses. In addition to supporting patient safety research, this 2-million-subject data source has been used in a number of epidemiology and health services research studies.