Coping with interoperability in the development of a federated research infrastructure: achievements, challenges and recommendations from the JA-InfAct
Authors: González-García Juan , Estupiñán-Romero Francisco , Tellería-Orriols Carlos , González-Galindo Javier , Palmieri Luigi , Faragalli Andrea , Pristās Ivan , Vuković Jakov , Misinš Janis , Zile Irisa , Bernal-Delgado Enrique ,   on behalf of the InfAct Joint Action consortium, Unim Brigid , Carle Flavia , Gesuita Rosaria , Ivanković Damir , Brkić Marko , Dimnjaković Jelena , Lyons Jane , Lyons Ronan , Ors Zeynep , Zaletel Metka , Nogueira Paulo , Lapão Luís Velez , Haaheim Håkon , Bogaert Petronille , Abboud Linda , van Oyen Herman 
Published: December 2021

Abstract
Background
Information for Action! is a Joint Action (JA-InfAct) on Health Information promoted by the EU Member States and funded by the European Commission within the Third EU Health Programme (2014–2020) to create and develop solid sustainable infrastructure on EU health information. The main objective of this the JA-InfAct is to build an EU health information system infrastructure and strengthen its core elements by a) establishing a sustainable research infrastructure to support population health and health system performance assessment, b) enhancing the European health information and knowledge bases, as well as health information research capacities to reduce health information inequalities, and c) supporting health information interoperability and innovative health information tools and data sources.

Methods
Following a federated analysis approach, JA-InfAct developed an ad hoc federated infrastructure based on distributing a well-defined process-mining analysis methodology to be deployed at each participating partners’ systems to reproduce the analysis and pool the aggregated results from the analyses. To overcome the legal interoperability issues on international data sharing, data linkage and management, partners (EU regions) participating in the case studies worked coordinately to query their real-world healthcare data sources complying with a common data model, executed the process-mining analysis pipeline on their premises, and shared the results enabling international comparison and the identification of best practices on stroke care.

Results
The ad hoc federated infrastructure was designed and built upon open source technologies, providing partners with the capacity to exploit their data and generate dashboards exploring the stroke care pathways. These dashboards can be shared among the participating partners or to a coordination hub without legal issues, enabling the comparative evaluation of the caregiving activities for acute stroke across regions.
Nonetheless, the approach is not free of a number of challenges that have been solved, and new challenges that should be addressed in the eventual case of scaling up. For that eventual case, 12 recommendations considering the different layers of interoperability have been provided.

Conclusion
The proposed approach, when successfully deployed as a federated analysis infrastructure, such as the one developed within the JA-InfAct, can concisely tackle all levels of the interoperability requirements from organisational to technical interoperability, supported by the close collaboration of the partners participating in the study. Any proposal for extension, should require further thinking on how to deal with new challenges on interoperability.