The MedDRA Paradox
Gary H. Merrill, Ph.D.
Abstract: MedDRA (the Medical Dictionary for Regulatory Activities Terminology) is a controlled vocabulary widely used as a medical coding scheme. However, MedDRA’s characterization of its structural hierarchy exhibits some confusing and paradoxical features. The goal of this paper is to examine these features, determine whether there is a coherent view of the MedDRA hierarchy that emerges, and explore what lessons are to be learned from this for using MedDRA and similar terminologies in a broad medical informatics context that includes relations among multiple disparate terminologies, thesauri, and ontologies.
Construction and Annotation of a UMLS/SNOMED-based Drug Ontology for Observational Pharmacovigilance
Gary H. Merrill, Patrick B. Ryan, Jeffery L. Painter
Abstract: The primary goal of the SafetyWorks project has been the development of an integrated set of methodologies enabling the use of large observational data sources in monitoring and assessing drug safety concerns. To support its analytical and exploratory capabilities, SafetyWorks makes use of two large hierarchically structured ontologies – one for medical conditions, and one for drugs. In this paper we focus on the drug ontology employed in SafetyWorks and on its construction and annotation based on the SNOMED CT and RxNorm subsets of the Unified Medical Language System Metathesaurus. The result is a case study illustrating the value of SNOMED and its integration with UMLS and RxNorm in a critical and innovative drug safety application. We expose sufficient details of our methods to enable others to make use of these methods and to encourage the expanded use of both SNOMED and the UMLS in data exploration and analysis applications, particularly in the area of improving approaches to drug safety.
