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MedDRA Primary System Organ Class

Hi Everyone,

I had a use case where I was utilizing the CDM to standardize some adverse event reports from the FDA Adverse Event Reporting System, but ran into an issue with the CDM’s export of MedDRA (Medical Dictionary for Regulatory Activities). The highest level in the MedDRA Hierarchy is System-Organ-Class (SOC). The adverse event reports, though, report at the Preferred Term level, and many PT’s are assigned to multiple SOC’s due to the ambiguity in how certain terms may be defined. The CDM export of MedDRA does not contain the flag for primary SOC, which is required for me to be able to determine which hierarchy I should primarily use. I was able to solve this by importing a full version of MedDRA in a stand-alone format, but in it’s current form the MedDRA hierarchy contained within the CDM is not complete. I’ve attached a small example of the adverse event reports table matched to MedDRA to show some examples of multiple SOC’s for the same PT, but no flag for primary SOC.

medDRA-cdm.xlsx (36.4 KB)


You are totally right. In the OMOP hierarchy, we do not make the distinction between primary parenthood and secondary, simply because it makes no sense. However, you need to be able to create reports that add up to 100%, and there you need a single parent hierarchy. We need the same thing for so-called “Table 1 summaries”, and we have something crude, but not yet fully standardized for OHDSI purposes.

We should do two things:

  • Introduce different “Is a” relationships for MedDRA. That won’t change the way the CONCEPT_ANCESTOR table works, but you could follow the relationships yourself - there are not that many strata in MedDRA.
  • Finish the Table 1 reporting. It’s already far along.