Proposed Pharmacy Data Element Ontology

One of the challenges in this project is preparation of an analyzable database. Pharmacy data elements are collected from pilot hospitals, refined/defined, and linked into longitudinal patient records appropriate for process and outcomes analysis. The major technical challenge in this phase is heterogeneity of the data elements. Each data source has its own method of data coding. They rarely speak the same language, either they choose different vendors' solutions or they have different definition for the same data field, or they just use free text. One particularly difficult element is prescription dosage. This element is complicated by the close relationship between dosage, dosage form, package size, and unit of measure. In any given instance each of these elements may, or may not, be the same. How much a patient received may be expressed as any of the following: one tablet, 500mg, 60ml, or one vial, each of which are technically correct, but difficult to work with without a quantity qualifier.