Interoperability Between Health Information Systems: Dead End in Large-Scale Sharing of Health Data?

This article provides a critical analysis of system-system interoperability (SSI) in the health data domain. By SSI, we mean the idea of connecting technical systems with each other to exchange operational data, directly or via intermediate platforms or infrastructures. We start by giving a brief history of some uses of the word “interoperability,” from the Institute of Electrical and Electronics Engineers (IEEE) original definition in 1991 to the Interoperable Europe Act of 2024. We thereby identify ambiguity and hidden assumptions in the definitions themselves. We then establish precise terminology to make a stringent analysis possible. Aided by a simple case of SSI from our own clinical practice and using a method of logical analysis, we look closely at (1) the assumption that the semantics in SSI can be handled by referring to external semantic standards, (2) the assumption that SSI is a feasible route to the safe exchange of operational data between systems in primary use, and (3) the challenges encountered in scaling SSI solutions to involve multidirectional data exchange, multiple data types, and multiple systems. Our first conclusion is that semantic interoperability, as defined by the Healthcare Information and Management Systems Society (HIMSS) in 2019, may not be a feasible route to stabilizing the real-world meaning of data exchanged in SSI solutions. The main reason is that referring to external standards cannot capture enough contextual information to correctly interpret health data remote from the primary context in which they were first registered. Our second conclusion is that SSI may not be a feasible route to the exchange of operational data between systems in primary use. Multiple unresolved problems are identified—problems that cannot be overcome by adding new components to existing systems, as proposed in, for example, the European Health Data Space (EHDS) legislation. Instead, a thorough redesign of each system’s internal architecture, data model, and user interface to align them with each other would be required. It is far from clear how such redesign would be practically achievable. Our third conclusion is that SSI may not be a scalable solution. In part, this is a consequence of the difficulties in using external standards to handle the semantics. Instead, careful negotiations and agreements about the exact meaning of each data type to be exchanged would be needed to guard against misinterpretation and, hence, risks in both primary and secondary use. We conclude that interoperability should be repositioned from being a taken-for-granted pathway to “better use of health data” to being an explicit object of critical inquiry. Further research should establish a commonly agreed analytical framework for evaluating suggested solutions. This framework must include stringent definitions of concepts and terminology, theoretical requirements, and practical aspects to be addressed in a concrete implementation.