[The role of drug registries in the post-marketing surveillance].

The aim of this article is to provide an introduction to issue of Recenti Progressi in Medicina, devoted to the role of drug registries in the post-marketing surveillance. We first motivate the need to implement registries as a tool in promoting the appropriateness of drug use and acquiring additional information on the risk-benefit profile of drugs. Then, the different role that can be played by registries in comparison with prescription monitoring systems and observational studies is clarified. The presentation of some of the most relevant registries established in Italy since the end of the '90s, with the analysis of their strengths and weaknesses, helps to understand some of the crucial issues that should be taken into account before a new registry is adopted. Specifically, we deal with the relationship between objectives - of appropriateness, effectiveness and safety - and methods; the overlapping between drug-based registries and disease-based ones; the duration and extension of data collection, which may be either exhaustive or based on a sampling frame; the importance of ensuring the quality of the data and to minimize the number of subjects who are lost to follow-up; the importance of infrastructures, and of ad hoc funding, for the functioning of a registry; the independence in data analysis and publication of findings.