Semantic interoperability of dual-model EHR clinical standards

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1 Semantic interoperability of dual-model EHR clinical standards Catalina Martínez-Costa Departamento de Informática y Sistemas, Facultad de Informática Universidad de Murcia, CP 30100, Murcia cmartinezcosta@um.es Abstract. Semantic interoperability of clinical standards is a major challenge in the ehealth across Europe, because this would allow health care professionals to manage the complete Electronic Healthcare Record (EHR) of patients independently from the institution in which each clinical session was generated. Archetypes are considered a cornerstone to deliver fully interoperable EHRs and they are built for particular EHR standards. This work is focused on the development of methods and techniques for providing semantic interoperability between dierent EHR standards at archetype level. 1 Introduction Semantic interoperability intends to ensure that the precise meaning of exchanged information is understandable by any other system or application not initially developed for the same purpose. Recent recommendations of the European Commission [1,2] have stated that the semantic interoperability of EHR systems is essential to improve the quality and safety of patient care, public health, clinical research, and health service management. In order to manage that interoperability, the digitalization of the EHR has been a major research issue for the last decades. An increasing number of countries have been making eorts in the digitalization of EHRs since the GEHR project ( began the design of an electronic health architecture in the late 80s. As a consequence of those eorts, several EHR standards were proposed, including HL7 ( OpenEHR ( and ISO EN ( The availability of multiple standards has provoked that clinical information be distributed amongst dierent systems syntactically or semantically incompatible. This work focuses on providing methods for achieving the desired semantic interoperability, in particular, methods applicable to dual-model based standards [3] such as OpenEHR and ISO EN The dualmodel architecture is based on two modelling levels: information and knowledge. The information level is provided by the reference model and the knowledge level by the archetype model. Archetypes dene clinical concepts and are usually built by domain experts. They are a tool for building clinical consensus in a consistent way and they are considered basic to deliver fully interoperable EHRs [4].

2 Most of the currently available archetypes are described for OpenEHR wheareas ISO EN is likely to be widely used in European countries. Recently, ISO EN has been selected as the ocial EHR standard in Sweden [5] and is a candidate standard for the European project epsos (Smart Open Services for European Patients) ( Moreover, the usage of this standard has been recommended in the nal report of the Semantic Health project ( It should be noted that ISO EN and OpenEHR are likely to coexist in the near future, so the exchange, sharing and re-use of archetypes between these standards becomes an important issue. Clinical archetypes are dened using the Archetype Denition Language (ADL). This is a generic language that does not allow performing any semantic activity over archetypes such as comparisons, classication, integration of information and so on. The Semantic Web [6] technologies such as ontologies provide a semantic formalism that facilitate such knowledge-intensive tasks, and they will play an essential role in our approach. In [7] a representation of archetyeps as ontology instances is presented. They are derived from the semantic interpretation of both the ISO EN and OpenEHR reference and archetype models and are written in the Web Ontology Language (OWL) ( There, two main ontologies were built for each standard. The (ISO13606/OpenEHR)-SP ontologies represent the clinical data structures and datatypes dened in the corresponding standards, and (ISO13606/OpenEHR)-AR that are archetype model ontologies and re-use the SP ones. They are available in a public repository [8], and constitute the basic technological infrastructure for our research work. 2 Towards ISO EN and OpenEHR archetype-based semantic interoperability The representation of archetypes in a semantic way allows performing knowledge tasks on them and describing its information in a more natural way making it easier its access. This representation has been chosen to be used in the transformation process. Then, the rst step in our research work was the design and implementation of a methodology for getting semantic archetypes from syntactic ones. Then, the transformation of archetypes between both standards was achieved. Both results are explained next. 2.1 Transforming ADL syntactic archetypes into semantic ones For getting archetypes conforming to the previous ontological representation from the ADL ones we designed a technical solution that involves three technical spaces (TS) [9]: the Grammar TS to which ADL belongs, the Semantic Web TS to which ontologies belong, and the Model Driven Engineering (MDE) TS. This last one is the pivotal TS in which the transformation takes place hence it makes our transformation approach easy to maintain and to adapt to other ontological languages. In MDE a metamodel can be described as a collection of

3 related concepts in a certain domain and a model is considered as an instance of a metamdel.thus, metamodels from the OWL ontologies were obtained by using the ODM standard [10] that denes the representation of OWL ontologies in MDE TS. The methodology proposed for the transformation in the rst approximation [11] was optimized in [12] for getting better quality OWL archetypes. The evolution was purely technical, and it came from the lessons learnt from our previous work. Finally the transformation process is divided in the following three phases (see Figure 1): (1) the input ADL archetype is expressed as a syntactic model conforming to the archetype model; (2) this syntactic model is transformed into a semantic model by using a model to model transformation that denes the model to model mappings between the syntactic archetype metamodel and the ISO EN 13606/OpenEHR semantic one and (3) the semantic model is transformed into OWL according to the EHR ontologies by using a model to text transformation. Fig. 1. The ADL to OWL transformation process 2.2 Transforming archetypes between ISO EN and OpenEHR Both clinical standards, ISO EN and OpenEHR follow the dual model approach. They use the same syntactic model for dening archetypes but they dier in how they structure the EHR domain, that is, they dene dierent reference models. OpenEHR was devised to fully support the construction of EHR systems, whereas ISO EN was designed for exchanging EHR extracts. Every ISO EN entity has a similar one dened in OpenEHR, but the opposite does not happen because OpenEHR provides richer data structures and data types. For transforming OpenEHR archetypes into ISO EN and vice versa, a similar technological solution to the adopted in the ADL to OWL transformation has been used. The architecture of this solution is depicted in Figure 2. There, two layers can be distinguished, namely, ontology and MDE. The ontology layer comprises a series of ontologies that model EHR-related knowledge for the dierent standards. In particular, our current semantic infrastructure includes ontologies for ISO EN and OpenEHR, as described in Section 2.1, and a common ontology designed for representing archetypes from both standards. This last ontology was designed to develop a generic and extensible architecture, capable of dealing in the future with other standards such as HL7 v3 or Detailed Clinical Models (

4 The MDE layer contains the metamodels corresponding to the semantic representations dened in the ontology layer. Once the metamodels have been obtained, the correspondences amongst them were dened. In order to transform OpenEHR archetypes into their ISO EN representation and vice versa, the mappings were dened between the particular standard and the Common metamodel. These mappings have been conceptually dened at concept and property levels and implemented using a model transformation language. In addition, model to text rules have been dened and applied to the target metamodel to obtain the ADL archetype textual representation. The transformation of ADL OpenEHR archetypes into ADL ISO EN consists of the following four phases: (1) the ADL archetype input is transformed into a model conforming to the OpenEHR metamodel (OpenEHR model); (2) the OpenEHR model is transformed into the common archetype representation (Common model); (3) the Common model is transformed into ISO EN (ISO EN model) and (4) the ISO EN model is transformed into ADL code (ISO EN ADL archetype). Fig. 2. The ISO EN OpenEHR transformation process The last phase of the workow can be congured to produce an OWL archetype instead of an ADL one. The transformation from ISO EN to OpenEHR is similar, as the main dierence between both workows is the set of mapping rules applied in phases 2 and 3. Both results have been implemented into the Poseacle Converter, which is available at We have also produced a repository of automatically transformed archetypes, which is accessible from the converter. 3 Conclusions In this work, we have described our current results on the semantic interoperability between dual-model EHR standards. So far, we have been able to obtain an OWL representation of archetypes and methods for transforming archetypes

5 between such standards. To the best of our knowledge, this is the rst implementation of archetype transformation between such standards, although there are other proposals pursuing similar goals, such as [13,14]. The next step is to reuse our previous results to develop methods for the automatic transformation of data instances. Moreover, since we have developed semantic models for representing and transforming archetypes. semantic query models will also be researched. References 1. Semantic Interoperability for Better Health and Safer Healthcare. Deployment and Research Roadmap for Europe Commission Recommendation of 2 July 2008 on cross-border interoperability of electronic health record systems (notied under document number C(2008) 3282) Beale, T.: Archetypes and the ehr. Stud Health Technol Inform 96 (2003) Kalra, D., Tapuria, A.: The ehr and clinical archetypes: time for clinical engagement! In: ehealth Planning and Management Symposium. (2008 November; Copenhagen, Denmark) 5. A national decision in Sweden on healthcare informatics standard 2008: _swedish_decision.doc (cited 2010 May) 6. Berners-Lee, T., Hendler, J., Lassila, O.: The semantic web. Scientic American May (2001) Fernandez-Breis, J., Vivancos-Vicente, P., Menarguez-Tortosa, M., Moner, D., Maldonado, J., Valencia-Garcia, R., Miranda-Mena, T.: Using semantic technologies to promote interoperability between electronic healthcare records' information models. In: Proc. 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society EMBS '06. (Aug Sept ) Poseacle repository: researchehr/websvn/ (cited 2010 May) 9. Kurtev, I., Bezivin, J., Aksit, M.: Technological spaces: an initial appraisal. In: CoopIS, DOA'2002 Federated Conferences, Industrial track,. (2003) 10. OMG: Ontology metamodel denition specication. (2006) 11. Martinez-Costa, C., Menarguez-Tortosa, M., Fernandez-Breis, J., Maldonado, J.: A model-driven approach for representing clinical archetypes for semantic web environments. J. of Biomedical Informatics 42(1) (2009) Martinez-Costa, C., Menarguez-Tortosa, M., Maldonado, J., Fernandez-Breis, J.: Semantic Web technologies for managing EHR-related clinical knowledge. In: Semantic Web. ISBN (2010) Chen, R., Klein, G., Sundvall, E., D.Karlsson, Ahlfeldt, H.: Archetype-based conversion of ehr content models: pilot experience with a regional ehr system. BMC Medical Informatics and Decision Making 9(33) (2009) 14. OpenEHR to ISO EN mapping: /stds/openehr+to+iso ,+iso mapping (cited 2010 May)