Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: st: epiconf: counfounding
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: epiconf: counfounding
Date
Tue, 8 Feb 2011 00:55:31 +0000
-epiconf- is a user-written program (Z. Wang, STB-49).
Nick
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
>
>
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/