OHDSI Home | Forums | Wiki | Github

The meaning of 'minDaysAtRisk' argument



I don’t know the meaning of ‘minDaysAtRisk’.
This argument is used in ‘createStudyPopulation’ function.
I consulted the manual but I still don’t know.
Is this the argument that limits the period between outcome start date and end date?

Thank you.

(Martijn Schuemie) #2

Subjects having less than minDaysAtRisk are removed.

You can use the other argument to specify the start and end of the time-at-risk (typically relative to the cohort start and end date). Some people may have more time-at-risk than others. Using minDayAtRisk you could for example limit the analysis to only those that are at least 365 days at risk.

Note that this is a tricky parameter to play with, because you are using information post-index to define who is included in your study. It may very well be that the people that are longer at risk are those that tolerate the treatment well, and don’t drop out for other reasons such as death. This could lead to bias.