Proc sql: 6 mth look back period from a specific event (SAS 9.4)

[ajb]

Hi,

I am currently learning proc sql and I am trying to figure out how to code a 6 month look back period for EVENT. In my data set everyone has had EVENT. I  would like to look back 6 months pre EVENT to determine if anyone in my data set filled a prescription for DRUG. I created a flag for whether or not a person has ever filled a prescription (1=yes, 0=no) and I also have the date of drug fill. An example of some of the variables in the the data set is presented in the table below.

How do I create a table with only people who filled the drug in the 6 month look back period?

ID	EVENT_DATE	DRUG 1/0	Drug_fill_date
2	2/5/00	1	3/12/99
2	2/5/00	1	4/11/99
2	2/5/00	1	30/09/99
3	3/2/04	1	3/1/04
3	3/2/04	1	3/12/03
4	4/3/09	0
5	3/5/08	1	5/9/07
6	4/3/11	0

This is a bare bones version of the code I ran using proc sql

data eg1;
      set eg1;
                  (where=(start = ('event_date'-180)  and end ='event_date'));
run;

proc sql;
     create table eg2 as

        select * from eg1

        where start<= Drug_fill_date<= end

      ;

quit;

Can you please help me to figure out where I have gone wrong in this code?

[andreas_lds]

Posting data in usable form is always a good idea to get more helpful answers than this one 😉

The variables "event_date" and "drug_fill_date" are sas-dates, right?

You are using the variables "start" and "end" - i can't see them in the table you posted.