@mlbernauer MedDRA isn’t standard vocabulary for OHDSI. So as much as possible concepts will be mapped to standard vocabularies (most common SNOMED) with relationships “Maps to” / “Maps to value”. Currently we continue this work. You can use hierarchical relationships between concepts inside the MedDRA vocabulary or inside the SNOMED separately. But as @Alexdavv wrote above due to MedDRA/SNOMED hierarchy discrepancies we’ll not plan to merge the MedDRA and SNOMED hierarchies in any way.