Re: effect of diseases on length of stay

Posted by Richard Ristow on Jan 23, 2007; 12:04am
URL: http://spssx-discussion.165.s1.nabble.com/no-subject-tp1073249p1073262.html

Follow-up to original thread "effect of diseases on length of stay"

At 11:59 AM 1/16/2007, Angshu Bhowmik wrote:

>I have data on lengths of hospital stay (LOS, in days) in about 100.
>There are various co-morbidities: Disease B, Disease C etc which may
>be present or absent. I want to find out if any of the co-morbidities
>are increasing (or decreasing)  LOS e.g. Does disease C increase
>length of stay independently (and if it is possible to find out, by
>how much)?

I suggested ANOVA, with the reservation that it might be necessary to
transform the data, mainly because length-of-stay curves tend to be
long-tailed. (That is, a majority of patients clustered around short to
moderate lengths of stay, with a minority having much longer ones.)

A couple of other posters suggested survival analysis, which is
certainly reasonable: a datum is, after all, duration to a terminal
event. (Don't tell the patients I'm calling discharge 'terminal'.)

Question, then: Survival analysis is necessary if you have censored
data, i.e. subjects of whom you know only that the terminal event
occurred after a certain date. But this set has no censored data.

Is there an active reason, then, not to use ANOVA? I ask because ANOVA
procedures generally have more flexibility, apart from handling
censoring, than do survival-analysis procedured.

-Ignorant, but anxious to learn,
  Richard