Since the establishment in 1999, more than 600 scientific pharmacoepidemiological studies have been performed by the PHARMO Institute and collaborating universities for PhD thesis support, governmental organisations and pharmaceutical industry on strict protocolled guidance.
As many ideas, the first discussion about linkage of community pharmacies and the National Dutch Hospital Registration (LMR) started in a pub in the harbour of Rotterdam between prof. dr. B.Ch. Stricker and dr R.M.C. Herings in 1988. The first experiments to link drug exposure files to hospital administration records date back to the first quarter of 1989. In the absence of a unique patient identifier, a semi-deterministic linkage was established between both databases, based on the combination of date of birth, gender and GP identification number in a small village in the north of the Netherlands. The following years the linkage algorithms evolved from deterministic to validated Bayesian-probabilistic models. In 1993, the PHARMO Record Linkage System was established as an updateable working system covering a population of approximately 300.000 inhabitants. As with all record linkage systems that link data from different organisations, contracts had to be in place to protect the primary objective of the single individual databases. In 1997, the SIG, a cooperative of all Dutch hospitals and the University of Utrecht, decided to explore the possibility to establish a new, financial independent organisation responsible for the governance, maintenance, collection, linkage, privacy protection and analysis of data obtained from both organisations.
In December 1999, the PHARMO Institute was established and the first pharmacoepidemiological studies were performed addressing mainly adverse drug reactions from a societal-scientific perspective. In subsequent years the number of pharmacies contributing to the system increased from 30 to 400, and is still growing. Furthermore, new proprietary databases were build in collaboration with hospitals, general practitioners and clinical laboratories and linkages were expanded to linkages with for example the Dutch Pathology Registers (PALGA), the Eindhoven Cancer Registration (IKZ), Dutch mortality statistics (CBG) and the Netherlands Perinatal Registry (PRN). A major characteristic of these expansions is that the PHARMO Institute focuses on geographic and demographic defined areas where complete coverage of the population is established (denominator) and where unique anonymised patient numbers are implemented that enables the follow-up of patients for exposure and medical events for some patients for more than 20 years.