Managing Incompatible FHIR Implementation Guides in a Single Backend: Namespace-Based Storage in Neo4j and...

Area of Science:

• Health Informatics
• Computer Science
• Healthcare Systems Engineering

Background:

• Achieving healthcare interoperability relies on Health Level Seven Fast Healthcare Interoperability Resources (HL7 FHIR) Implementation Guides (IGs).
• Inconsistencies between international, national, and local IGs lead to inevitable incompatibilities, complicating data exchange.
• Mandatory implementation of multiple, unaligned IGs, as seen in Germany, creates significant practical challenges for healthcare applications.

Purpose of the Study:

• To systematically compare competing German HL7 FHIR Implementation Guides (KBV Base 1.x and ISiK Basismodul v2).
• To identify and document hard structural conflicts between these IGs.
• To propose a technical solution for managing data conforming to multiple, incompatible FHIR IGs.

Main Methods:

• Systematic comparative analysis of KBV Base 1.x and ISiK Basismodul v2 FHIR Implementation Guides.
• Identification of structural conflicts, including slicing and type constraints on key FHIR resources (Patient, Practitioner, RelatedPerson, Condition).
• Development of a namespace-based data management solution using Neo4j to handle data redundancy and multi-format delivery.

Main Results:

• Identified significant structural conflicts between the analyzed German FHIR IGs, such as closed vs. open slicing on Condition.onset[x] and disjoint constraints on address/name types.
• Demonstrated that a single FHIR resource cannot simultaneously conform to all three mandatory German IGs.
• Developed a Neo4j-based data management system capable of storing data without redundancy and serving it in multiple formats based on client profile requests.

Conclusions:

• HL7 FHIR Implementation Guide incompatibilities pose a significant barrier to practical interoperability.
• A namespace-based data management approach in Neo4j offers a viable technical solution for handling conflicting FHIR IG requirements.
• Future work should focus on integrating FHIR profile comparison tools, performance evaluation, and alignment with emerging standards like HL7 Europe EHDS.