Overview of drug data within French health insurance databases and implications for pharmacoepidemiological studies.

In this study, we aimed to provide an updated overview of drug data contained in the French health insurance database (SNIIRAM) and its associated national representative sample (EGB). This study identified most common problems concerning drug data: (i) change in level of coverage of drugs of interest (drug no more eligible for reimbursement or no more prescription-only), (ii) break in patients' eligibility (in connection with change of healthcare plan or patients' identifier), and (iii) technical and regulatory issues. We provide a brief checklist to enable a structured identification of these issues. The impact of gap in drug data availability on study validity will depend on the research question, drug, setting, and population of interest. The French health insurance database and associated sample are valuable resources for pharmacoepidemiological research. There is a need to pursue further methodological and validation studies to promote accurate and transparent use of French health insurance databases for pharmacoepidemiology.