[Use of the capture-recapture method to assess the frequency of "serious" adverse drug reactions: experience of Toulouse University Hospital]

Abstract

There is evidence that the methods classically used to identify and quantify adverse drug reactions (ADRs), based on spontaneous reporting or computerized medical databases, are not exhaustive. Spontaneous notifications to regional pharmacovigilance centers suffer from under-reporting Combining different sources could improve our knowledge of ADR frequency. The aim of this study was to estimate the incidence of serious ADRs handled in medical wards of a French university hospital, using data from the Programme de Medicalisation des Systemes d'Information (PMSI) and spontaneous reports recorded in the French Pharmaco Vigilance Database. The study period was the first 6 months of 2001. From the PMSI, we selected all hospitalization summaries that included an ICD-10 code related to a potential ADR. From the French Pharmaco Vigilance Database, we selected all serious ADRs that occurred during the study period and were reported by physicians working in the University Hospital. After identifying cases recorded in both sources, we applied the capture-recapture method in order to estimate the real number of ADRs. From the PMSI, we identified 274 different hospital stays involving an ADR. Out of 241 reports selected from the French Pharmaco Vigilance Database, we retained 151 ADRs for analysis. Fifty-two ADRs were found in both databases, giving an estimated total of 796 serious ADRs [95% confidence interval (CI) 638, 954], corresponding to 2.9% of inpatients (95% CI 2.3, 3.5) during the first half of 2001. This study confirms the lack of exhaustiveness of ADR reporting, whatever the data source, and underlines the value of merging data from different databases.