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Re: st: Cox multilevel
From
Ronán Conroy <[email protected]>
To
"[email protected]" <[email protected]>
Subject
Re: st: Cox multilevel
Date
Wed, 17 Nov 2010 13:31:08 +0000
On 16 Nov 2010, at 15:34, Celine Genty wrote:
I am trying to make a multilevel model of survival data, so with the
-shared()- option.
I have about 5000 patients included by 300 center.
But 45 center have only 1 patient (with a median of 7 patients per
center IQR 3-21).
Is multilevel model appropriate in this case ? Is there too much
center
? Is there too much center with only 1 patient ?
If you really want to examine the effects of context (centre, in your
case) then clearly you need an informative sample of patients from
each context.
It seems to me that you might begin with the obvious: the number of
patients per centre is probably a good index of turnover, and you
might wonder if patients at centres with high turnover had a
different disease profile and a different prognosis. Different
disease profile because the more difficult patients tend to get
referred onwards to the centres of excellence, and different
prognosis because the busy hospitals are supposed to be the centres
of excellence.
Ronán Conroy
[email protected]
Associate Professor
Division of Population Health Sciences
Royal College of Surgeons in Ireland
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