Case Reports as Evidence in Pharmacovigilance

© 2014 by John Wiley & Sons, Ltd. All rights reserved. Anecdotal reports of suspected adverse drug reactions can be useful in several ways: to describe a newly recognized or suspected adverse reaction or interaction; to generate and test hypotheses; to demonstrate diagnostic techniques; to elucidate mechanisms; to elucidate or suggest methods of management; to remind or educate; and to add to the database of unpublished reports, thus enhancing signal detection. Sometimes a single anecdote, or a small number taken together, can even provide definitive proof that a drug and an adverse event are causally associated. If enough case reports have been published, a systematic review may yield useful information. Registries of patients receiving specific therapies for specific diseases are being increasingly used in postmarketing surveillance of medications. Modern data-mining methods of analyzing large databases containing information about individual cases have proved powerful in detecting signals of previously undetected harms and also benefits. The International Conference on Harmonisation has produced documents, under the general title E2B, that prescribe the format in which data about individual cases of suspected adverse reactions should be reported as part of drug development. A comparable method of reporting individual cases to journals is included here, based on previously published methods. Adoption of this method by journals that publish case reports of suspected adverse drug reactions would usefully increase the information available and enhance the quality of systematic reviews.