Could Swedish 'yellow cards' be substituted by E-coded summaries?

Case summaries of 2490 patients treated at the Department of Infectious Diseases, Danderyd Hospital, in 1986 were reviewed for discharge diagnoses where the International Classification of Disease (ICD) code indicated an adverse drug reaction (ADR) [E 939,9 in ICD 8]. Of 48 patients whose case summaries indicated an ADR, only 10 (21%) had been reported on 'yellow cards' to the Swedish Adverse Drug Reactions Advisory Committee. The Committee had also received from the same department 3 reports where the case summary lacked an ADR code. The information on drug treatment with respect to dosage, duration and treatment with concomitant drugs was not complete in the case summaries but sufficient for a preliminary evaluation of the suspected reactions in all but 4 of the cases. On the basis of these findings the authors do not reach an outright conclusion in favour of replacing the 'yellow card' system but the possible benefits of a system in which 'yellow cards' are supplemented by automatic referral of all case summaries containing an ICD code indicating an adverse drug reaction was judged sufficient to recommend and initiate a large field study.