Migration from HL7 Clinical Document Architecture (CDA) to Fast Health Interoperability Resources (FHIR) in Infectious Disease Information System of Estonia.

Objective : Many countries have successfully implemented HL7 V3 and CDA (Clinical Document Architecture) standards to ensure document-based interoperability between EHRs (Electronic Health Records), registries, and healthcare institutions [26] [32] [5]. The biggest drawback of the HL7 CDA document-based approach is the timing of sharing the information. The document is generally shared once all the agreed data elements have been precisely filled in and the necessary confirmations received. Today, Estonia is transitioning the Estonian National Health Information System (ENHIS) from a document-based approach to an event-based approach by utilising the HL7 FHIR (Fast Healthcare Interoperability Resources) standard. During this transition, one of the tasks is to describe the patient's socioeconomic status according to the FHIR profile. Method : As part of the project, the CDA-based notification of infectious patients, including patients' socioeconomic status, in the Infectious Disease Information System (NAKIS - the acronym of the system in Estonian) of Estonia is analysed. This analysis pays special attention to education and employment data, which is currently part of patients' socioeconomic status. The existing employment and education-related FHIR profiles, openEHR clinical models and SNOMED and LOINC terminology are studied to find appropriate specifications for patients' socioeconomic status. Results : As a result of the project, similar and/or suitable FHIR resources and terminology will be chosen. Structural changes will be made in the data collection process, where several simple values will be selected instead of one complex value. New FHIR profiles will be created, modelling new FHIR-based data structures and describing the terminology. Summary : It is possible to reuse information from existing official sources rather than collect it from patients. Socioeconomic status is a temporal representation of the patient's education, employment and other similar information about the patient. We propose a universal and reusable methodology for migrating HL7 CDA documents and their components into FHIR resources.