Methodological issues in using prescription and other databases in pharmacoepidemiology

摘要

Development in technology has led to a considerable increase in the number of individual-based registersand databases, that may be of value in pharmacoepidemiological research, and the number of studies thatare based on these secondary data may be expected to increase. The focus of this paper is to review methodologicalproblems related to use of such databases in pharmacoepidemiological studies with respect to thefour basic types of associations which can be observed in an observational study: 1) bias, 2) confounding,3) chance or 4) causal. The following factors will affect the value and validity of registries and databases:1) the completeness of registration of persons, 2) the validity and degree of completeness of the registereddata, 3) the size of the data source, 4) the registration period, 5) data accessibility, availability, and costs, 6)data format, and 7) the possibilities of linkage with other data sources. The importance of these issuesdepends on the use of the data and on the problems they have to address. The Nordic countries have aunique possibility of record-linkage between registries because of the civil registry number assigned toevery citizen at birth. In pharmacoepidemiological research this gives us the opportunity to study differentoutcome events in relation to drug use, and this has been extensively used in the Danish pharmacoepidemiologicalapproach. The Nordic countries could play a leading role in future pharmacoepidemiologicalresearch. This, however, requires considerably more efficient and comprehensive use of the collected dataon which the society has spent many resources for other purposes.