Hi Collinelliot,
Either one of the below data sets is what I desire to get. It can be listing the date or replacing the date by YES flag variables. The first table below is telling, for instance, the patientID=1 does not have any treatment history happenning 6 month before the index date, so the mindate_pre6month is missing or the flag is missing. The patientID=1 has treatment records happened between pre 6 month and post 6 month of index date, and among those records, the miniumen treatment date is 9/30/2008, so the second flag for patient=1 is YES.
And I tried your code, it works. It gives me the second table. GREAT!! Thank you. By the way, if I want the first table below, how can I modifiy your code? Thank you so much!
patient ID
mindate_pre6month
mindate_pre6month_post6month
mindate_post6month
1
.
9/30/2008
.
2
1/1/2010
9/30/2010
.
3
12/30/2009
8/1/2011
12/13/2011
4
.
6/8/2009
3/1/2010
…
…
…
…
patient ID
flag1_pre6month
flag2_pre6month_post6month
flag3_post6month
1
.
yes
.
2
yes
yes
.
3
yes
yes
yes
4
.
yes
yes
…
…
…
…
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