Classification of ADR Reports

CLASSIFICATION OF ADR REPORTS

Each report must be assigned to one or more drugs and to one or more medical terms describing the reaction. There is a need for a distinction between a drug reported as being suspected of causing the adverse effect and one that is simply co-medication. This distinction made by the reporter of the reaction may not be made correctly, especially when it is an interaction between drugs that is causing the effect.

For the value of the report to be optimal, both the trade name and the drug substance name may need to be recorded separately. For initial statisti-cal approaches to signal detection the drug substance name is the one that is used.

The minimum information for a valid report is usually an identifiable (but not necessarily identified) patient, a drug and a reaction. The reaction must be classified using some form of medical dictionary. There are several different dictionaries in wide use, including those from the Food and Drug Adminis-tration (FDA) (COSTART) and the World Health Organisation (WHO) (WHO-ART). In the United Kingdom, the Medicines Control Agency (MCA) use their own Adverse Drug Reactions Online Information and Tracking (ADROIT) dictionary and a project to unify these dictionaries, based partly on the ADROIT dictionary has been carried out, resulting in the inter-nationally (International Conference on Harmonisa-tion (ICH)) agreed MedDRA.

Most of the dictionaries have a form of hierarchy from the widest grouping – ‘System Order Class’, for exam-ple cardiovascular – through ‘High Level Terms’ to ‘Preferred Term’, for example myocardial infarction. A second type of classification relates to the public health impact of a reaction classed as fatal, serious or non-serious. The definition of ‘serious’ is not always consistent between countries or dictionaries but within a particular database it will (or should) be consistent.