D4.3 OMOP-CDM extensions

The report provides a systematic methodology that combines general rules-of-thumb for data mapping with targeted, modality-specific recommendations. The approach is grounded in a thorough review of OHDSI community-driven conventions, ongoing working group outputs, and lessons learned from past integration efforts. Best practices emphasize use of the standardized OMOP tables and vocabularies wherever possible, reserving project-specific or local extensions only when absolutely necessary. The methodology encourages balancing pragmatic interim solutions with active engagement in, and contribution to, relevant working groups, ensuring that chosen conventions remain robust, interoperable, and future-proof as the OMOP ecosystem evolves.