Dear Statalisters,
I have data on patients, readmissions, and deaths:
. list ptid doadmit doreadm dod
+----------------------------------------------------+
| ptid doadmit doreadm dod |
|----------------------------------------------------|
1. | 00000125 29 Aug 1996 14 Nov 96 20 Oct 1997 |
2. | 00000133 20 Jul 1991 . . |
3. | 00000491 21 Mar 1997 . 26 Jun 1999 |
4. | 00000865 06 Mar 1996 . . |
5. | 00000932 13 May 1997 11 Jul 97 . |
|----------------------------------------------------|
6. | 00001354 04 Jun 1994 . . |
7. | 00001610 10 May 1995 . . |
8. | 00001804 24 Sep 1996 . 12 Jul 1997 |
9. | 000020 20 Aug 1992 . 09 Sep 1993 |
10. | 000025 28 Oct 1996 . 24 Aug 1999 |
|----------------------------------------------------|
11. | 000034 20 Nov 1992 07 Jan 93 . |
...
I want to examine readmissions only up to 90 days post-discharge, so I
create an extra variable, 'dolast':
generate dolast=dodischg+90
format dolast %dD_m_CY
But all of the observations with doreadm==. are, obviously, missing. So
when I -stset- my data, I obtain the following results:
. stset doreadm, id(ptid) time0(doadmit) origin(time doadmit)
failure(event) exit(event==2 time dolast)
id: ptid
failure event: event != 0 & event < .
obs. time interval: (doadmit, doreadm]
exit on or before: event==2 time dolast
t for analysis: (time-origin)
origin: time doadmit
------------------------------------------------------------------------
------
23324 total obs.
18608 event time missing (doreadm>=.) PROBABLE
ERROR
------------------------------------------------------------------------
------
4716 obs. remaining, representing
4716 subjects
4716 failures in single failure-per-subject data
184319 total analysis time at risk, at risk from t = 0
earliest observed entry t = 0
last observed exit t = 90
What I would like to do is:
a) I would like to remove patients from the study if they die within 90
days post discharge. But I can't have two time variables in the exit
option -- for example, (exit time dod dolast). So what I did is set
event==2 for death (event==1 for readmission).
b) How do I keep the patients with no readmission in the study? I
thought about replacing doreadm=dolast if doreadm==. but that doesn't
seem right.
Cleves/Gould/Gutierrez' book "An Introduction to Survival Analysis Using
Stata" has been exceedingly helpful, but I am stuck here. I'd be
grateful for any help.
Thanks,
Alex
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