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Atlas: How to set index date to absolute day or to get_todays_date()


(Vojtech Huser) #1

For a cohort that finds patients for a review by case manager, I need to have criteria relative to index date that is somewhat different from typical OHDSI cohorts.

Is it possible to set the index date in Atlas for a cohort to some absolute day (e.g., April 1, 2020) or to today minus 20 days)? From the SQL logic, I know it should be possible.

If it is not possible within Atlas (which I think is the case), I will file a github issue about this - but I wanted to be sure I did not miss anything.

Here is the click in Atlas where I need to select an absolute date: Add Initial Event (options there)


(Chris Knoll) #2

create an observation period cohort entry event, and use the option to ‘specify start and end date’ If you just want a single date, then just set the start date = end date…I recommend you do this.

Btw: this criteria will automatically only include those people who have an observation period that covers the specified dates. If you do something like 2013-01-01 to 2018-01-01, only people who have a single observation period that spans this range will be included in the cohort.


(Vojtech Huser) #3

Thanks.
Here is the cohort I just created using your guidance
http://atlas-demo.ohdsi.org/#/cohortdefinition/1774429

I need the cohort end date to be wide (for cohort pathway analysis) (so I used offset from start date to have cohort end date to be +365 days after my absolute index date of jan 1 2017.

If I got something still wrong, let me know.


(Chris Knoll) #4

That’s fine, just remember that even tho you ask for 365 days, some people may end their cohort at the end of observation before the 365 days. Therefore, if you want to require that they have the 365 days, you can specify the observation period must end after jan 1 2018.


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