topic Re: calculate a change within a specific interval date. in SAS Programming

Re: calculate a change within a specific interval date.

PhanS — Sun, 30 Sep 2012 20:36:55 GMT

Dear SAS Help,

In the data below, I want to calculate cd4 changes within a specific interval date '12-month' from the first test.

Any help, I much appreciate. Thanks in advance.

Obs id CD4COUNT CD4DATE cd4 cd4date last_cd4 cd4date 12month cd4

1 20 332 29MAY2006 332 29MAY2006 6 03NOV2009 29MAY2007 326

2 20 267 12JUN2006 332 29MAY2006 6 03NOV2009 29MAY2007 326

3 20 207 05DEC2006 332 29MAY2006 6 03NOV2009 29MAY2007 326

4 20 71 20NOV2007 332 29MAY2006 6 03NOV2009 29MAY2007 326

5 20 15 24JUN2008 332 29MAY2006 6 03NOV2009 29MAY2007 326

6 20 8 07AUG2008 332 29MAY2006 6 03NOV2009 29MAY2007 326

7 20 3 02JUN2009 332 29MAY2006 6 03NOV2009 29MAY2007 326

8 20 6 03NOV2009 332 29MAY2006 6 03NOV2009 29MAY2007 326

9 40 20 30JAN2003 20 30JAN2003 326 14DEC2010 30JAN2004 -306

10 40 10 13MAR2003 20 30JAN2003 326 14DEC2010 30JAN2004 -306

11 40 300 08MAY2003 20 30JAN2003 326 14DEC2010 30JAN2004 -306

12 40 239 19JUN2003 20 30JAN2003 326 14DEC2010 30JAN2004 -306

Re: calculate a change within a specific interval date.

art297 — Sun, 30 Sep 2012 21:46:20 GMT

Based on your example, what do you want the resulting dataset to look like?

Re: calculate a change within a specific interval date.

PhanS — Sun, 30 Sep 2012 22:11:16 GMT

Dear Sir,

I am relatively new with longitudinal analysis, but this is part of study. I want the resulting in long format as I will study change in cd4 in relationship with initial antiretroviral class.

Sincerely,

Re: calculate a change within a specific interval date.

art297 — Sun, 30 Sep 2012 22:24:12 GMT

Understood, but for any of us to help, we have to see want you want to achieve. It would also be useful to see what you have already tried to accompomplish what you want.

Re: calculate a change within a specific interval date.

PhanS — Sun, 30 Sep 2012 22:35:19 GMT

Dear Sir,

For instance, id 20, I want to calculate a difference between cd4=332 (first date) and cd4=71 (20Nov2007) in which this date is the nearest one year after the first test.

Also, id 40, a difference between cd4=20 (30Jan2003) and cd4=239 (19Jun2003) that the date is nearest one year after the first test.

Thanks.

Re: calculate a change within a specific interval date.

PGStats — Mon, 01 Oct 2012 00:47:11 GMT

Hi! Try this way :

proc sort data=have; by id CD4DATE; run;

data want;
do until(last.id);
     set have; by id;
     if first.id then do;
          firstDate = CD4DATE;
          firstCD4 = CD4COUNT;
          end;
     else do;
          delay = abs(intck("DAY", firstDate, CD4DATE) - 365);
          minDelay = min(delay, minDelay);
          if minDelay = delay then do;
               yearCD4 = CD4COUNT;
               lastDate = CD4DATE;
               end;
          end;
     end;
format firstDate lastDate date9.;
keep id firstDate firstCD4 yearCD4 lastDate;
run;

proc print; run;

Re: calculate a change within a specific interval date.

PhanS — Mon, 01 Oct 2012 01:41:08 GMT

Dear Sir,

I greatly appreciate and thank you very much for your time in helping me this task. I ran the analysis and checked results that are exactly I am looking for.

Again thanks,

Sincerely,

Re: calculate a change within a specific interval date.

Linlin — Mon, 01 Oct 2012 01:59:13 GMT

Please mark your question as answered and gave PG and Art credits for helping you. If you don't know how to mark your question as answered please ask. Thank you!

Re: calculate a change within a specific interval date.

PhanS — Mon, 01 Oct 2012 02:06:25 GMT

Dear Linlin,

I appreciate your friendly reminding me. Please tell me as I am relative new for the community. I am not sure where I can give a mark.

I look forward to hearing from you soon.

Re: calculate a change within a specific interval date.

PhanS — Mon, 01 Oct 2012 02:10:33 GMT

Hi Linlin,

I just clicked correct answer. Am I doing the right way?

Re: calculate a change within a specific interval date.

Linlin — Mon, 01 Oct 2012 02:28:22 GMT

Yes!