topic Sum of variables based on date in SAS Programming

Sum of variables based on date

CJK7 — Thu, 24 Oct 2024 19:12:18 GMT

I have a wide form dataset in which each patient has multiple MME measures (MME_1 - MME_153) and a corresponding date (Order_Date_1 - Order_Date_153). Each patient has a pre and post intervention period, based on the variable index_date. I need to create a variable that is the sum of all MME measures in the pre period and another variable that is the sum of all MME measures in the post period.

Re: Sum of variables based on date

PaigeMiller — Thu, 24 Oct 2024 19:45:20 GMT

This is incredibly easy with a long data set and PROC SUMMARY. You can use PROC TRANSPOSE to create the long data set. If you provide a small example of the data with say 10 patients, 3 variables and the corresponding 3 dates and the pre and post intervention dates, I can provide code. Use these instructions to provide data as SAS Data step code. Do not attach files or show us screen captures.

Re: Sum of variables based on date

mkeintz — Thu, 24 Oct 2024 22:21:46 GMT

You can use two arrays, each with 153 elements - one array for the dates, and one for the mme values. Then just iterate through the 153 elements of each array, test the date and add the mme to the pre- or post- summary value, as appropriate:

data want;
  array odate order_date_1 - order_date_153;
  array mme   mme_1        - mme_153;
  do over odate;
    if odate>index_date then post_sum=sum(post_sum,mme);
    else if odate>. then pre_sum=sum(pre_sum,mme);
  end;
run;

Re: Sum of variables based on date

CJK7 — Wed, 30 Oct 2024 13:07:45 GMT

I wasn't able to provide the example data, but your comment did put me on the right path. I was able to manipulate the data as needed in long form, then transpose back to wide form. Thanks!