RE: st: epiconf: counfounding

[Nick Cox <n.j.cox@durham.ac.uk>]

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 
n.j.cox@durham.ac.uk 

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 <njcoxstata@gmail.com> wrote:

> -epiconf- is a user-written program
> (Z. Wang, STB-49).

> On Mon, Feb 7, 2011 at 10:43 PM, SR Millis <aa3379@wayne.edu>
> 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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