Applying Bidirectional Transformations to the Design of Interoperable EMR Systems

Interoperability between heterogeneous health information systems has remained an elusive goal despite decades of exchange standards development and implementation initiatives. Empirical studies have shown that in many cases, implemented interoperability interfaces fail to function correctly. Unfortunately, the health informatics literature provides little guidance on how to best design and assure interoperability interfaces. Still, healthcare is not the only industry that requires the exchange of highly complex semantic data structures. Similar requirements can be observed in the engineering industry, where complex data models maintained by various types of development tools and environments must be synchronized over a product's life cycle. Research on how to best address this challenge has led to the development of the concept of bidirectional transformations (BX) and associated design theories, methods, and tools. While BX approaches have received little attention in e-Health interoperability applications to date, we believe that they can also facilitate the implementation and assurance of interoperability in that domain. In this paper, we cast the health information exchange (HIE) challenge as a BX problem, review applicable BX theories, and discuss their practical applications from the perspective of software engineers who are tasked with constructing and assuring bidirectional interoperability interfaces for health information systems. We further design a proof-of-concept interoperability interface using BX design methods in the context of a real-world interoperability standard initiative. We compare the new BX-based interoperability interface with a preexisting, conventionally designed implementation. We find that the BX design offers similar runtime performance while providing improved maintainability, testability, and modularity.