Determinants of signal selection in a spontaneous reporting system for adverse drug reactions

Abstract

Aims Detection of new adverse drug reactions (ADR) after marketing is often based on a manual review of reports sent to a Spontaneous Reporting System (SRS). Among the many potential signals that are identi®ed, only a limited number are important enough to require further attention. The goal of this study is to gain insight into factors contributing to the selection and dissemination of possible signals originating from the SRS maintained by the Netherlands Pharmacovigilance Foundation. Methods In a case control design, all signals (n=42) disseminated to the Medicines Evaluation Board from the second quarter of 1997 until the third quarter of 2000, which could be expressed as a combination of a single ATC code and a single WHO preferred term, were included. For each case, four controls were matched in time. Logistic regression analysis was used to investigate the in¯uence of various factors, such as the fact whether the ADR or drug is new, the strength of the association, the seriousness of the reaction and the documentation of the reports. Results Multivariate analysis showed that the presence of a`serious report' (Odds Ratio 3.8, 95% CI 1.3, 11.0), a WHO`critical term' (OR 4.7, 95% CI 1.8, 13), the ADR being unlabelled (OR 6.1, 95% CI 2.3, 16) and the presence of a disproportionate association (OR 3.5, 95% CI 1.4,8) were all independently associated with signal selection. The number of reports and the time after marketing of the drug had no in¯uence. Conclusions This study showed that selection of signals is based on both qualitative and quantitative aspects. Knowledge of these factors may improve the ef®ciency of the underlying signal selection process.

Sudden and unexpected deaths after the administration of hexavalent vaccines (diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B, Haemophilius influenzae type b): is there a signal?

“…This possibility cannot be ruled out with case ascertainment from a spontaneous reporting system. A spontaneous reporting system can generate a valid signal, however, as reported for Vaccine A [19].…”

Analysis of Neuropsychiatric Adverse Events in Patients Treated with Oseltamivir in Spontaneous Adverse Event Reports

“…14,15,20) RORs were expressed as point estimates with a 95% CI. A signal is considered an event when the lower limit of the ROR 95% CI is ≥1, 20) and at least 3 cases were required to define the signal. We refined the signal with a dedicated correction to detect possible confounding factors present in the database.…”

Adverse drug reactions: Analysis of spontaneous reporting system in Europe in 2007–2009

“…The latter is currently considered to be the most effective tool to collect adverse drug reaction (ADR) reports [3]. The SRS was established to collect post-approval safety information that would lead to the early detection of new or rare ADRs [4].…”