Linkage of Routine Data to Other Data Sources in Germany: A Practical Example Illustrating Challenges and Solutions

Routine data have a high potential for epidemiological and health care research but lack information, for instance, on the cause of death. Often detailed information, such as on lifestyle factors is also missing. In Germany, obtaining the missing information by linkage to data sources is challenging, mainly due to strict data protection regulations. One key challenge arises from the fact that routine data users usually have no access to person identifiers which would be necessary for record linkage. A second key challenge is that sensitive information (i. e., the cause of death) should not be transferred to an institution that holds person identifiers. In this paper, we illustrate these key challenges and present corresponding solutions based on a practical example where claims data from statutory health insurance providers are linked to an epidemiological cancer registry to obtain cause of death information. We describe the approval procedures necessary for the record linkage, the dataflow between the involved institutions and explain the rationale of the dataflow in view of the key challenges. Finally, we generalize the questions that need to be addressed when a record linkage is planned and point to additional potential challenges. Overall, we illustrate that a linkage between routine data and other data sources in Germany is feasible, but specific restrictions and hurdles need to be taken into consideration.