Hi
I am going to explore a cancer type
in UK biobank research platform
When I use ICD9 I find 9 participants but when I use ICD10 as filter I find 4000 participants
I am sure which ICD I should trust
Any of you has exprience with UK RAP system?
The only way to answer this question is to know what the research question of interest is. Without that knowledge it is impossible to choose one or the other. Once you know that, you need to study what are the differences between ICD9 and ICD10 codes for the individuals that are the same and different, then try to figure out why the results are so discrepant.
We cannot help you with any of that without more information.