Generating psychotropic drug exposure data from computer-based medical records

Purpose: To develop a methodology for extracting psychotropic drug exposure data from computer-based medical records and for generating drug exposure variables suitable for secondary use. Methods: In South-Verona, Italy, a registry including every patient receiving psychotropic medications is operating since 2004. The basic structure of the registry is the medication record. Each record stores data on a specific prescription, and patients with more than one prescription have more than one record. Results: The longitudinal history of drug use was described identifying consecutive prescriptions of a specific drug, concomitant prescriptions of a specific drug and distinct prescriptions of a specific drug. Consecutive prescriptions implies that the beginning of the second prescription coincides with the end of the first prescription, concomitant prescriptions implies that the beginning of the second prescription precedes the end of the first prescription, distinct prescriptions implies that a gap of at least 1 day exists between prescriptions. Using this framework of drug representation, we identified episodes of drug therapy, where each episode is constituted of consecutive and/or concomitant prescriptions. Within each episode, prescriptions were categorised into theoretical phases, where the beginning of the new phase always coincides with the end of the previous phase. On the basis of this data representation, a module operating in Access and using Visual Basic for Applications was developed for creating episodes and phases on a routine basis (available from authors). A graphical representation of this conceptual model is presented. Conclusion: The development of a simple methodology for extracting and generating drug exposure data suitable for secondary use will allow a better understanding of the beneficial and adverse consequences of psychotropic drug use in ordinary practice. © 2006 Elsevier Ireland Ltd. All rights reserved.