European network for the case-population surveillance of rare diseases (Euronet). A prospective feasibility study.

OBJECTIVE: Euronet, a case-population surveillance scheme, aims to estimate the risk of certain rare conditions which are commonly iatrogenic, by comparing drug use amongst non-selective cases with overall drug use in the general population.
METHODS: The method is based on three provisos: (1) all incident cases (irrespective of suspected aetiology) should be ascertained and studied; (2) a full drug history should be obtained from cases by direct interview; and (3) drug-use data for the products of interest should be available for this population from which cases are chosen. The feasibility of this problem-oriented approach for the identification of new signals of adverse drug reactions and for risk estimation will be tested in relation to agranulocytosis, Stevens-Johnson syndrome and toxic epidermal necrolysis in four defined areas in Europe, totalling 19 x 10(6) inhabitants, with these latest two outcomes being studied in only three regions. The design, methods and main limitations of this case-population surveillance approach are described.