Medical Dictionary for Regulatory Activities (MedDRA)

Medical Dictionary for Regulatory Activities (MedDRA), as the ICH approved standard terminology for all drug regulatory activities, is in many aspects different from previously used terminologies, mainly in size, specificity, structure, rules and conventions. All these aspects impact on retrieval strategies, analysis and presentation of the coded data.After shortly describing the key features of MedDRA and their theoretically anticipated impact on data analysis and presentation, two examples for display of MedDRA coded data are described, one from a clinical study project and one from spontaneous reporting. The first example compares the adverse drug reaction (ADR) profile of the same data coded in WHO Adverse Reaction Terminology (WHO-ART) and recorded in MedDRA; the second example demonstrates different ways of presenting the ADR profile of an antibacterial, using different elements in MedDRA with the aim of presenting the ADR profile in a way that best transports the medical concepts reported with this drug.Based on some results obtained from these examples and based on analysis of the content of MedDRA version 6.0, the following limitations of MedDRA for data analysis have been identified: (i) the Preferred Term level is generally too granular, bearing the danger of underestimating risks, and the midlevels are currently not a robust, consistent and non-ambiguous level for data aggregation; and (ii) the rules relating to multiaxiality add complexity for data aggregation because related medical concepts may be split into different System Organ Classes, which may mislead frequency analysis.In the absence of guidance from regulatory agencies and with the growing need for analysis of MedDRAencoded data, there is a risk of diminishing the benefits of MedDRA as a standard terminology through the use of user-specific and non-standardised data analysis and presentation strategies.MedDRA would benefit from a redesign of the group terms (High Level Group Terms/High Level Terms) to become a robust, consistent and non-ambiguous level for data analysis and aggregation. This should be done in an interdisciplinary effort coordinated by the MedDRA Maintenance Supply and Support Organisation (MSSO).