warn when using ICD-10-CM instead of presumptive WHO ICD?

[jackwasey]

At least two issues have arisen because of this. It should be clear, but flooding user with warnings is not ideal either.

Possible solutions:

• warn every time
• message every time
• warn or message first time only (after each package load)
• only warn or message for some functions, e.g. explaining a code in plain language.
• detect specifically when a code fails in one system when it would work in the other. This would be computationally expensive, and complicated to implement. At a minimum, we would have to look-up in WHO and CM systems, and do something if they differ (and they may differ only in punctuation, etc.)

The icd10 or icd9 type imply a specific system, but the WHO and US Clinical Modifications overlap, but neither is a subset of each other. For many operations, like decimal notation to non-decimal notation, this doesn't matter.

Other suggestions welcome.