Creating knowledge about adverse drug reactions: a critical analysis of the Danish reporting system from 1968 to 2005

Data on adverse drug reactions (ADRs) have been collected in Denmark since 1968 and the process is ongoing. This article explores knowledge created by the system, including how the collected data have been used to monitor the safety of licensed drugs. Nonaka's theory of knowledge creation was used to discriminate between tacit and explicit knowledge. A total of 56,802 ADR case reports were received from 1968 to 2005. The analysis shows a rather stable number of ADR cases from 1980, with about 2000 reports per year. The distribution of cases into serious and non-serious ADRs has been one to four throughout the period under study, but with large variations. Analysis of selected ADR cases shows that the system lacked the potential to capture available knowledge. Consequently the ADR reports have had limited value and significance in the process of creating scientific knowledge. Thus, the analysis questions the way available data can become explicit as a basis for regulatory decisions and whether all data can become knowledge, including who decides what knowledge is.