To understand whether SNOMED CT is suitable to act as a core reference terminology for supporting EU-wide eHealth deployments existing experiences of the use of ASSESS CT and other large-scale terminology systems have been investigated.
SNOMED CT was seen as a core reference terminology in a terminology ecosystem. Any semantic interoperability strategy needs to consider the coexistence of a set of standard terminologies : Neither SNOMED CT, nor any other terminology, even limiting the scope or the domain, can be the “unique” solution.
Reference terminologies of the eco-system should be related to national and international aggregation terminologies to support secondary uses and administrative processes.
ASSESS CT sought empirical evidence for the fitness for purpose of SNOMED CT, compared to other terminologies. Four studies were conducted:
• Evaluation of semi-automatic creation of terminology interface terms
• Terminology coverage analysis on international EHR (Electronic Health Record) samples
• Use of terminologies for manual and automated annotation of unstructured data
• Use of terminologies for structured data entry
The conclusion of these studies is that SNOMED CT is equally well suited as an alternative UMLS (Unified Medical Language System) extract for clinical text annotation and better for the binding of terminology codes to clinical models. For all languages and terminology settings, inter-coder agreement needs to be improved.
Only the English SNOMED CT provides an acceptable inventory of interface terms, whereas for German, French and Dutch, the UMLS is a good source for clinical interface terms. Therefore, user interface terminology aspects need to be emphasised, not primarily as parts of localised SNOMED versions but rather as separate artefacts. The role of user interface terminologies is especially important in the automated processing of clinical texts.
ASSESS CT developed policy recommendations on the adoption of large-scale (international) clinical terminologies, such as SNOMED CT, as part of a national and/or European strategy towards advancing the semantic interoperability of health data.
Recommendation 1: Any decision about the adoption and role of terminological resources, including SNOMED CT, must be part of a wider, coherent and priority-driven strategy for optimizing the benefits of semantic interoperability in health data.
A European terminology strategy should be part of an overarching European eHealth strategy. The strategy should support the principles of collecting clinical data once and using them multiple times, where allowed and required. Thus, administrative, public health and research information should almost always be derived from routinely collected clinical information.
This strategy should have Member State commitment and should consider human and financial resource implications, incentives, as well as technical and semantic requirements.
Recommendation 2: SNOMED CT is the best available candidate for a core reference terminology for cross-border, national and regional eHealth deployments in Europe.
A main advantage is its content coverage, which is superior to any other single terminology, making it the most complete point of reference for health related concepts. Another advantage of SNOMED CT over a set of other clinical terminologies is its principled ontology-based architecture with a logic-based coordination syntax.
Recommendation 3: SNOMED CT should be part of an ecosystem of terminologies, including international aggregation terminologies (the WHO Family of Classifications), and including national interface terminologies, which address multilinguality in Europe and clinical communication with lay language and multidisciplinary professional language.
No country sees SNOMED CT as a standalone solution, but rather as an important part of the national terminology infrastructure.
Recommendation 4: The adoption of SNOMED CT should be realised incrementally rather than all at once, by developing terminology subsets that address the interoperability requirements for prioritised use cases, and expanding this set over some years.
Such incremental use, but across all Member States, might be subject to specially negotiated licences on behalf of the whole of European Union. Solutions must be in place for legacy conversion, guaranteeing the continued exploitation of historical data, for user interface terminologies, and for assuring the continuation of global mortality and morbidity statistics.
Recommendation 5: Mechanisms should be established to facilitate and co-ordinate European Member State co-operation on terminology and semantic interoperability, including common areas of governance across national terminology centres, eHealth competence centres (or equivalent national bodies).
This should maximise the value of Member State and SDO alignment on the approach to advancing semantic interoperability, including the implementation and deployment of SNOMED CT.
The prioritisation of the key drivers behind semantic interoperability, at European and Member State levels, is important in directing the downstream priorities of an implementation strategy.
