Yuimedi Evaluates OMOP Concept Mapping Coverage for All Entries in the MEDIS Standard Disease Name Master

Yuimedi, Inc. has published a peer-reviewed study in the Journal of Japan Association for Medical Informatics (Vol. 45, No. 6), evaluating the feasibility of mapping all entries in the MEDIS Standard Disease Name Master to OMOP standard concepts via ICD-10 codes. The MEDIS Standard Disease Name Master is one of the most widely used clinical terminologies in Japan.

Applied to all 27,564 disease names using automated, vocabulary-based mapping with OHDSI-managed vocabulary data, the study achieved a mapping success rate of 99.2%. It also systematically classified the entries that could not be mapped, identifying the structural factors behind each unmappable case.

Background

As real-world data (RWD)-based drug development and clinical research continue to expand globally, the OMOP Common Data Model has become a widely used framework for enabling international interoperability of health data.

Converting Japanese healthcare data to OMOP requires mapping Japanese disease names and domestic code systems to the standard concepts defined within OMOP. Yet until now, little systematic research has evaluated the practical limitations of this conversion at full-corpus scale, or the structural factors driving unmappable terms.

Key Findings

The study produced three clear findings.

Automated mapping via ICD-10 codes achieved a 99.2% success rate across all 27,564 disease names in the MEDIS Standard Disease Name Master. The remaining 0.8% of unmappable entries were classified into three structural categories:

• ICD-10 codes with supplementary numeric qualifiers

• ICD-10 codes with supplementary alphabetic qualifiers

• Entries with no ICD-10 code assigned

For each category, the study outlines practical mapping strategies with concrete examples, providing actionable guidance for improving reproducibility and automation accuracy in real-world OMOP conversion workflows.

Yuimedi's Expertise

Yuimedi's core strength is the operational depth of its OMOP conversion work, particularly in navigating the complexity of medical terminologies and code systems.

The approach in this study reflects that commitment: OMOP conversion that is transparent and reproducible, while accounting for the practical constraints of Japan-specific code usage and differences in coding granularity.

Outlook

Building on this research, Yuimedi will continue advancing the standardization of real-world data in Japan.

Japanese healthcare data is internationally recognized for its quality and comprehensiveness. Differences in medical terminology and coding systems, however, have kept it from being fully utilized in international research. Yuimedi is directly addressing this gap through OMOP conversion technology, working toward an environment where Japanese healthcare data can be used at a global standard.

About Journal of Japan Association for Medical Informatics

Published by the Japan Association for Medical Informatics (JAMI), this peer-reviewed journal covers research at the intersection of healthcare and information technology, including health data utilization, medical information systems, and clinical informatics. It serves as a key publication for disseminating research trends and practice-relevant insights in the field of medical informatics.

Online Journal: https://www.jami.jp/document/online-journal

About OMOP CDM

The OMOP Common Data Model (Observational Medical Outcomes Partnership Common Data Model) is an open community data standard maintained by OHDSI. Designed for the analysis of real-world observational data, it features a standardized vocabulary system capable of integrating medical terminologies from around the world, enabling a unified representation of real-world data across countries. Its normalized relational structure also makes it well-suited for observational research.