Inconsistent origin for `patient`

[prockenschaub]

While working on integrating SICdb #31, I noticed that the time origin for the ID level patient is inconsistently defined between datasets. For MIMIC, the origin is the date of birth whereas for AUMCdb, it is the earliest admission. I understand that this is due to the fact that not all databases allow calculation of the date of birth, but I was wondering, whether this should be unified (or documented) to avoid confusion? A consistent (although maybe not always helpful) origin for the patient could be the start of active observation for that patient. The end of observation would be loss of follow-up (if known, e.g., because the patient died) or NA if it is unclear if the patient is still under "observation".

[dplecko]

Thanks for noting @prockenschaub; There is a bit of discrepancy between datasets in terms of what is available, causing this issue. I think using active observation may turn out to be quite fiddly. Instead, I think documenting these differences would be helpful.

If you have a suggestion on where the best place to mention this is, please let me know. Otherwise, I will find a suitable place where this is mentioned.