Date:         Fri, 1 Sep 2006 09:37:25 -0400
Reply-To:     Kateri Heydon <heydon@EMAIL.CHOP.EDU>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Kateri Heydon <heydon@EMAIL.CHOP.EDU>
Subject:      drug duration

Hi, I need some help with the following data:

DRUG          DRUGDAY
A              1
A              2
A              3
A              7
A              8
A              9
B              1
B              2
B              3

How do I create code to determine drug duration by drug?  For example, I
need the duration for the first three days of A, and then the next 3 days
of A.  Since there is a break in usage, I want to count this as two
separate doses.  I know how to count doses and duration if there is no
breaks in usage, but where there is, I am very confused.
Thanks!