Assessing the impact of drug safety signals from the WHO database presented in 'SIGNAL': results from a questionnaire of National pharmacovigilance Centres.

Abstract

A major task for the Uppsala Monitoring Centre (UMC) is to detect early signals of suspected adverse drug reactions (ADRs) in the WHO Database. The database currently contains over 2.8 million spontaneously reported ADR case reports continuously collected by National Pharmacovigilance Centres in countries participating in the WHO Programme for International Drug Monitoring. The database is scanned every quarter and drug-ADR combinations are filtered out using different selection criteria intended to catch potential international drug safety signals at an early stage. Summary case data are reviewed by experts on the UMC's review panel and the signals are presented to the Programme members in the restricted circulation document entitled 'SIGNAL'. The aim of the study was to investigate: (i). how the signals presented in 'SIGNAL' are used; (ii). if they reach the right target group; (iii). if they are of interest and relevance to the recipients; (iv). if they are timely and; (v). if they make any difference. We were also interested in knowing the view of member countries regarding the definition of what a signal is. A questionnaire was sent out to 71 countries participating in the WHO Programme. The recipients were asked to state what actions were taken for 26 different signal headings included in three issues of 'SIGNAL' sent out during 2001 and to rate how useful they considered these topics to be. Responses were received from 45 countries (63%). The Centres' average ratings of relevance, importance and usefulness on a scale 1-10 of the selected 26 signals were all above the expected average rating 5.5. The content of 'SIGNAL' in general was seen as always or often useful in 63.5% of the respondents. In 2001, 17 countries took actions on at least one signal. Actions were rarely taken without considering the signal from the UMC. All responding centres agreed on the WHO definition of a signal, but there were differences in the interpretation of what constitutes a signal. The 'SIGNAL' publication is timely, plays an important role and has a direct impact on drug safety issues handled by members of the WHO Programme for International Drug Monitoring.