Study day calculation for DAY 0 visit.

day 0

According to the FDA, there is no day 0 in a clinical study. The start date is day is "1". The day before is day "-1".
If I had made such a statement at primary school, my teacher would have sacked me... ;-).

In order to calulate the study day, take the date and substract the start date. If the result is zero or positive, than add 1. If the result is negative, take the result for the study day.

This is well explained in the SDTM-IG. I need to check in which section and on which page.

Thank you very much!!

Thanks for your feedback.

Yes, it is there in the IG. But for that stdy protocol specified scheduled days are DAY -1, DAY 0, DAY 1....

So can i request CPM to ammend the protocol, to remove the DAY 0?

Day 0

Did the study start yet? Were any subjects already enrolled?
If not, I would surely ask CPM to ammend the protocol, and also add a paragraph why there is no day 0 (FDA requirement).
If data was already captured, when generating the SDTM/ADaM, just calculate the --DY values as explained before and according to the SDTM-IG.

Day 0

The study has already started and i have data with me.

Then i will proceed according to your suggestion.

Great Thanks for your suggestion.

Day Zero

I have multiple ongoing legacy studies (active for 2+ years all subjects enrolled) that were defined and programmed (SDTM & ADAM) with study day zero. It doesn't appear to be an error according to the rule but would it be rejected if submitted this way? Does it need to be changed?

visit day 0

P21 is not the FDA!
You should ask your question "would it be rejected if submitted this way?" to YOUR responsible FDA reviewer.
My experience is that there are as much FDAs as there are reviewers there. Each of them has its own preferences. So the answer to your question may well depend on which reviewer you get.

Remark that --DY variables are all "derived", they are NOT "collected". This means that however they were collected, you should convert to what the rule requires, this though the (math) logic conflicts to what I learned at primary school. Also, do not forget to document your derivation method in the define.xml (in the "MethodDef", referenced from the "ItemRef" with def:Origin being "derived".

Sergiy

on July 25, 2023

P21

Hi,  The most safe and…

Hi, 

The most safe and correct way is to fix your study protocol wording.

Now, "Day 0" is the first day of your study, "Day 1" is the second day of your study. It's quite confusing. There is no word in English (at least I am aware of) for the zero(st/nd/rd) day of the study. 

Kind Regards,
Sergiy