[Outpatient billing data from private health insurance - Part 1: Basics and requirements for scientific use]

In contrast to statutory health insurance (SHI) data, private health insurance (PHI) billing data have scarcely been used for scientific purposes in health and healthcare-related research and epidemiology. To date, findings can be obtained for 87.3% of people with health insurance in Germany based on analyses of SHI data. Often, however, only parts of the entire range of services covered by the SHI are depicted on a project-specific basis, depending on the data provided by the various cooperating health insurance funds. This means that statements can be made about the vast majority of the insured population. Nevertheless, a substantial proportion of the insured population is missing, meaning that no general validity for the entire population has been achieved to date. In addition to the 10% of people with comprehensive PHI, it has not been possible with the previous study focus on SHI data to conduct empirical research on the approximately 29 million people who have statutory health insurance and supplementary private insurance. This gap can be closed by supplementing the data on those with SHI with data on those with PHI. Accordingly, the research data center (FDZ) for health is planning to include private health insurance billing data. Yet there is a number of differences between SHI and PHI data, especially regarding the outpatient physician data, knowledge of which is a prerequisite for the proper analysis and interpretation of PHI data. This first article in a three-part series on the scientific use of PHI data on outpatient care and pharmaceutical prescriptions provides a systematic overview of the methodologically and analytically relevant similarities and differences between the two insurance systems based knowledge gained to date. In addition, the most important terms for the PHI sector are listed in the form of a glossary and the administrative and pragmatic requirements for the scientific use of PHI data are explained.