Towards the usage of German claims data vocabularies for research in OMOP CDM: Development and evaluation (Preprint)
Authors: Henke Elisa , Zoch Michéle , Kallfelz Michael , Ruhnke Thomas , Leutner Liz Annika , Spoden Melissa , Günster Christian , Sedlmayr Martin , Bathelt Franziska 
Published: April 2023

BACKGROUND

National classifications and terminologies already routinely used for documentation within patient care settings enable the unambiguous representation of clinical information. However, the diversity of different vocabularies across healthcare institutions and countries is a barrier to achieve semantic interoperability and to exchange data across sites. The Observational Medical Outcomes Partnership (OMOP) Common Data Model (CDM) enables the standardization of structure and medical terminology. It allows mapping of national vocabularies into so-called standard-concepts representing normative expressions for international analyses and research. Within our project “Hybrid quality indicators using machine learning methods (Hybrid-QI)”, we faced the challenge of harmonizing source codes used in German claims data vocabularies currently not available in OMOP CDM.

OBJECTIVE

The objective of this study is to increase the coverage of German vocabularies in OMOP CDM. With our work, we want to achieve the complete transformation of source codes used in German claims data to OMOP CDM without data loss as well as making German claims data usable for research based on OMOP CDM.

METHODS

To prepare the missing German vocabularies for OMOP CDM we defined a vocabulary preparation approach consisting of the identification of all codes of the corresponding vocabularies, their assembly in machine-readable tables and the translation of German designations into English. Furthermore, we used two proposed approaches for OMOP-compliant vocabulary preparation: the mapping to standard-concepts using the OHDSI tool Usagi and the preparation of new 2-billion-concepts. Finally, we evaluated the prepared vocabularies regarding completeness and correctness using synthetic German claims data and calculated the coverage of German claims data vocabularies in OMOP CDM.

RESULTS

With our vocabulary preparation approach, we were able to map three missing German vocabularies to standard-concepts and to prepare eight vocabularies as new 2-billion-concepts. The results of the completeness evaluation showed that the prepared vocabularies cover most of the source codes contained in German claims data. From the results of the correctness evaluation, it can be seen that the specified validity periods in OMOP CDM are compliant for the majority of source codes and associated dates in the German claims data. The calculation of the vocabulary coverage showed a noticeable decrease of missing vocabularies from 55% to 10% due to our preparation approach.

CONCLUSIONS

By preparing a total of ten vocabularies, we were able to show that our approach is applicable to any type of vocabulary used in a source dataset. The prepared vocabularies resulting from our work are currently limited to German vocabularies, which can only be used in national OMOP CDM research projects. Reason for this is a missing mapping of new 2-billion-concepts to standard-concepts. To be able to participate in international OHDSI network studies with German claims data, future work is required to map the prepared 2-billion-concepts to standard-concepts.