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RE: st: epiconf: counfounding
From
Nick Cox <[email protected]>
To
"'[email protected]'" <[email protected]>
Subject
RE: st: epiconf: counfounding
Date
Tue, 8 Feb 2011 09:38:54 +0000
I don't doubt that you know. But you are asked to make it clear whenever you refer to user-written programs, which you didn't do. My Googling identified Zhiqiang as having moved to the University of Queensland.
Nick
[email protected]
SR Millis
Nick,
Yes, I know that epiconf is a user-written program. I've try to contact Wang using the email address listed in STB-49 but Wang is no longer at that address. Googling failed to turn up alternatives.
Nick Cox <[email protected]> wrote:
> -epiconf- is a user-written program
> (Z. Wang, STB-49).
> On Mon, Feb 7, 2011 at 10:43 PM, SR Millis <[email protected]>
> wrote:
> > I've been working with your Stata program, epiconf.
> Using theaccompanying dataset and fitting the following
> logistic regression model:
> >
> > . epiconf dead ab_uria, con(age weight) cat(hichol
> hypert smoke sex) backward
> >
> > I obtained the following results. How do you
> interpret the model when the changes in the absolute values
> of the change in the odds ratios are not monotonically
> increasing (in the case of backward selection) or, in the
> case of forward selection, monotonically decreasing? That
> is, in this model, if we take 10% as the cut-point of
> importance, we need only adjust for age, smoking, and
> weight? If so, how do you obtain the adjusted rate ratio
> and its confidence interval?
> >
> >
> > Assessment of Confounding Effects Using
> Change-in-Estimate Method
> > Outcome: "dead"
> > Exposure: "ab_uria"
> > N = 743
> >
> > Backward approach
> > Potential confounders were removed one at a time
> sequentially
> >
> > Adj Var 95% CI Change in OR
> p
> >
> > Crude 2.35 1.24, 4.44 .
> .
> > -i.sex 2.26 1.21, 4.24 -3.6
> 0.47664
> > -i.hichol 2.08 1.12, 3.86 -8.0
> 0.15144
> > -weight 1.88 1.04, 3.40 -10.0
> 0.21915
> > -i.hypert 2.00 1.13, 3.55 6.6
> 0.42812
> > -i.smoke 2.24 1.28, 3.92 11.9
> 0.06456
> > -age* 3.90 2.34, 6.52 74.4
> 0.00000
> >
> > *Crude estimate
> >
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