Date:         Fri, 25 Jan 2008 14:51:34 -0800
Reply-To:     gopilth@YAHOO.COM
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         gopilth@YAHOO.COM
Organization: http://groups.google.com
Subject:      Calculating time intervals
Comments: To: sas-l@uga.edu
Content-Type: text/plain; charset=ISO-8859-1

Hi,
I need to calculate the time intervals for each visit from the day of
diagnosis.

Pt may have multiple visits with the same diagnosis  and also other
visits with a different diagnosis.
Following is the type of data I have.

Pt    diag_dt      serv_dt   visit_typ
1     22jan07      23jan07   hiv
1     22jan07      13frb07   sup
1    22 jan07      20mar07  tot
1    22jan07       30mar07  hiv
1    22jan07       03jul07    sup
1    22jan07       20jul07    tot
2    10feb07      15feb07    tot
2    10feb07     01mar07    hiv
2    10feb07     25mar07    tot
2    10feb07     03apr07     tot
2    10feb07     15may07   sup
2    10feb07     25jul07      hiv
2    10feb07     10aug07     sup
3    15feb07     25feb07     sup
3    15feb07     30mar07    hiv
3    15feb07     15apr07     hiv
3    15feb07     25may07   tot

For example pt " 1" in the above example has total of 6 visits 2 for
hiv treatment, 2 for supportive care and two for other reasons.
From this I want to calculate the time intervals between each visit
for all 3 types of visits i.e   Time b/w diag_dt  and 1st serv_dt  for
tot
       Time b/w diag_dt  and 2nd serv_dt  for tot
       Time b/w diag_dt  and 3rd  serv_dt  for tot and soon... until
last visit date.
Then for
       Time b/w diag_dt  and 1st serv_dt  for hiv
       Time b/w diag_dt  and 2nd serv_dt  for hiv
       Time b/w diag_dt  and 3rd  serv_dt  for hiv and soon... until
last visit date.
Then for
       Time b/w diag_dt  and 1st serv_dt  for sup
       Time b/w diag_dt  and 2nd serv_dt  for sup
       Time b/w diag_dt  and 3rd  serv_dt  for sup and soon... until
last visit date.

I hope this is clear. Thanks in advance
Gopi