You are pointing out an important problem: In a hierarchical system of concepts, are there strata we can use for various purposes that have the right level of granularity for reporting purposes? You have one use case, the typical rolled-up Table 1 reporting on conditions and treatments is another one. This has been discussed before.
We don’t have a solution for that, unfortunately. You could be part of creating the solution!
If you are working in OMOP you shouldn’t use source concepts. If they are properly mapped you should focus your conceptset on the standard concepts. If they are not mapped you should get them mapped.
The only thing I can think of is the phenotype library.
See answer to 1.
Usually, you need to roll up beyond the ingredient into ATC.
