Alathea is an R package that tracks changes to the Cohort definition resolution depending on the vocabulary version it’s run on (assuming the CDM is made on the same vocabulary version).
Same medical events (source codes) can be mapped differently in different vocabulary versions,
Concept hierarchy can be changed
Concept Domain can be changed as well as the standard status.
Due to these changes different medical events might define your cohort in different vocabularu versions.
Usually changes are small - the latest vocabulary update significantly affected 3 cohorts out of 1479 in JnJ Phenotype library (we run this tool routinely with each vocabulary update. But we always need to know which cohorts and how are affected to use these definitions reliably.
Also such a comparison is a crucial step in running collaborative studies when data partners have data with different vocabulary versions. By running it the users can be sure that the cohort definitions work similar, and if not, create additional cohort definition for another vocabulary version .
It’s explained how to use in the readme.md in the package repo
this is a real code run example - you’ll just need to change the variables and set keyring accordingly
You can also run it against OHDSI Phenotype library
See examples of the output tables as well