Announcement

Collapse
No announcement yet.
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • how to model medication exposure as a time varying exposure

    Hello all

    I am trying to do a survival analysis where I am looking at the whether a clinical score (X) is associated with my outcome of death. I want to adjust for a medication that is prescribed which influences both the clinical score and the risk of death. X is a continuous variable, but I have a dichomotomized version X_di.
    I have two databases, and in database 1, I have the following variables: id, age, sex, ethnicity, X, X_di time_of_origin, death_time, and death. Times are all in stata format.
    Database 2 has id, drug_start_date, duration of prescription (days), but with multiple records per id (range is 1-500 prescriptions per id). The drug start date is in stata format.

    Example of second dataset using dataex

    Code:
    * Example generated by -dataex-. For more info, type help dataex
    clear
    input long id float drug_date long drug_dur
    1002964 19575 28
    1002964 19604 28
    1002964 19631 28
    1002964 19659 28
    1002964 19687 28
    1002964 19708 28
    1002964 19708 28
    1002964 19768 28
    1002964 19775 28
    1002964 19810 28
    1002964 19855 28
    1002964 19879 28
    1002964 19904 28
    1002964 19939 28
    1002964 19962 28
    1002964 19988 28
    1002964 20016 28
    1002964 20038 28
    1002964 20072 28
    1002964 20102 28
    1002964 20131 28
    1002964 20156 28
    1002964 20186 28
    1002964 20209 28
    1002964 20237 28
    1002964 20270 28
    1002964 20298 28
    1002964 20326 28
    1002964 20326 28
    1002964 20376 28
    1002964 20409 28
    1002964 20436 28
    1002964 20436 28
    1002964 20492 28
    1002964 20520 28
    1002964 20548 28
    1002964 20579 28
    1002964 20591 28
    1003434 20570 56
    1003768 19638 28
    1003768 19673 28
    1003768 19701 28
    1003768 19733 28
    1003768 19757 28
    1003768 19768 28
    1003768 19787 28
    1003768 19823 28
    1003768 19871 28
    1003768 19898 28
    1003768 19932 28
    1003768 19957 28
    1003768 19977 28
    1003768 19992 28
    1003768 20019 28
    1003768 20052 28
    1003768 20075 28
    1003768 20118 28
    1003768 20136 28
    1003768 20170 28
    1003768 20195 28
    1003768 20234 28
    1003768 20257 28
    1003768 20279 28
    1003768 20314 28
    1003768 20341 28
    1003768 20367 28
    1003768 20395 28
    1003768 20419 28
    1003768 20458 28
    1003768 20478 28
    1003768 20514 28
    1003768 20537 28
    1003768 20569 28
    1003768 20598 28
    1003843 17192 28
    1004863 20191 56
    1004863 20234 56
    1004863 20296 56
    1004863 20354 56
    1004863 20410 56
    1004863 20464 56
    1004863 20521 56
    1004863 20583 56
    1004863 20632 56
    1004863 20688 56
    1004863 20744 56
    1004863 20795 30
    1004863 20857 56
    1004863 20915 56
    1004916 16768 28
    1004916 16786 28
    1004916 16820 28
    1005157 19534 30
    1005157 19547 30
    1005157 19568 30
    1005157 19597 30
    1005157 19619 30
    1005157 19652 30
    1005157 19680 30
    1005157 19708 30
    end
    format %td drug_date
    I'm wondering how I go about modelling this drug as a time varying exposure. Would I have to use stset then stsplit after combining the two databases? Or do I have to manipulate the data in the second database first? There is only one dose for this drug - hence will not have to weight it.

    Many thanks for your time!

  • #2
    I think it is best to combine the data sets first, and then run -stsplit-. Probably it would work just as well doing it the other way around, but in general once you have -stsplit- your data it is safest not to do manipulate it any further and just go immediately into your survival analysis.

    Comment


    • #3
      Thank you Clyde!

      Comment

      Working...
      X