I have a data set of individual level data for the outcome in question. I also have aggregated data (at a national level) from which I'm obtaining the denominator. Using this information, I've determined the annual incidence of the condition (after a certain exposure) over a 20 year period. Each individual can only get the disease once and then no longer contributes to the person-time.
I am then removing a subset of individuals whom I believe are being over-diagnosed. My intent was to show the difference in the incidence rates over time between when these individuals are included in the data set vs when they are excluded.
Now, my question is -- how do I compare these two annual incidence rates over time --- especially given that they are not two distinct populations.