User journeys in cross-European secondary use of health data: insights ahead of the European Health Data Space.

The European Health Data Space (EHDS) regulation aims to facilitate cross-border sharing of health data across Europe. However, practical challenges related to data access, interoperability, quality, and interpretive competence remain, particularly when working with health systems across countries. This study aimed to evaluate and report the user journey of researchers accessing and utilizing health data across four European countries for secondary research purposes prior to implementation of EHDS. We conducted a narrative reflection of individual and collective experiences on key aspects of the user journey-discovery, access, use, and finalization. Data were gathered from various structured and unstructured sources, including an online log, prospective questionnaires, regular meetings, and interviews. Researchers faced challenges at different steps of the user journey, which included lack of data quality in national metadata catalogues (discovery stage). Differences in national regulations led to inconsistent timelines for gaining access to data (access stage), with approval times ranging from a few months to over a year. At the use stage, researchers experienced challenges in harmonizing health data due to variations in coding practices and data quality. Issues related to computational capacity caused further delays. Substantial challenges must be addressed for EHDS to succeed. Establishing knowledge hubs, fostering collaborations, and streamlining access processes are essential. Close collaboration with experts will likely be essential for an effective user journey. This analysis underscores the importance of collaboration, analytical reproducibility, and clear documentation to ensure the success and timely delivery of cross-border projects.