Hi all,
I want to calculate hazard ratio within each covariate
Example, one covariate has 3 classes (1,2 and 3) and x2 has 2 classes
I want to compare the relative risk ratio within each class of the covariate.
How do I get this result ? .
The other question is that how do I interpret the second column in
the second panel (i.e., exp(-coef))
I used the model
coxfit1 <- coxph(Surv(sdat$time, sdat$cens)~ y1+x2)
coef exp(coef) se(coef) z Pr(>|z|)
y1 -0.024084 0.976204 0.003077 -7.828 5.00e-15 ***
x2 0.036161 1.036822 0.083921 0.431 0.6665
exp(coef) exp(-coef) lower .95 upper .95
y1 0.9762 1.0244 0.9703 0.9821
x2 1.0368 0.9645 0.8796 1.2222
Thanks in advance
On Dec 10, 2009, at 8:33 AM, Ashta wrote:> Hi all, > > I want to calculate hazard ratio within each covariate > > Example, one covariate has 3 classes (1,2 and 3) and x2 has 2 classes > > I want to compare the relative risk ratio within each class of the > covariate. > How do I get this result ? .Code as factors instead of numeric.> > The other question is that how do I interpret the second column in > the second panel (i.e., exp(-coef))It is the effect of a decrease by one unit of that variable.> > I used the model > coxfit1 <- coxph(Surv(sdat$time, sdat$cens)~ y1+x2) > > coef exp(coef) se(coef) z Pr(>|z|) > y1 -0.024084 0.976204 0.003077 -7.828 5.00e-15 *** > x2 0.036161 1.036822 0.083921 0.431 0.6665 > > exp(coef) exp(-coef) lower .95 upper .95 > y1 0.9762 1.0244 0.9703 0.9821 > x2 1.0368 0.9645 0.8796 1.2222 > > > Thanks in advance >David Winsemius, MD Heritage Laboratories West Hartford, CT
David,
Thank you very much for your response.
I fitted the model as factor instead of numeric.
coxfit1 <- coxph(Surv(sdat$time, sdat$cens)~factor(y1)+factor(x2)
coef exp(coef) se(coef) z
Pr(>|z|)
factor(y1)2 0.036161 1.036822 0.083921 0.431 0.6665
factor(y1)3 -0.510124 0.600421 0.088901 -5.738 9.57e-09 ***
factor(x2)2 -0.510124 0.600421 0.088901 -5.738 9.57e-09 ***
What are those values? Is it comparing in reference to the first
class of each covariate?
Thanks again.
On Thu, Dec 10, 2009 at 8:33 AM, Ashta <sewashm at gmail.com>
wrote:> Hi all,
>
> I want to calculate ?hazard ?ratio within each covariate
>
>
> Example, one covariate has 3 classes (1,2 and 3) and x2 has 2 classes
>
> I want to compare the relative risk ratio within each class of the
covariate.
> ?How do I get this result ? .
>
>
> The other question is that how do I interpret ?the second column in
> the second panel ?(i.e., exp(-coef))
>
> I used the model
> coxfit1 <- coxph(Surv(sdat$time, sdat$cens)~ y1+x2)
>
> ? ? ? ? ? coef ? ? ? exp(coef) ?se(coef) ? ? ? z ? ? ? ? ?Pr(>|z|)
> y1 ? ?-0.024084 ?0.976204 ?0.003077 -7.828 5.00e-15 ***
> x2 ? ? 0.036161 ?1.036822 ?0.083921 ?0.431 ? 0.6665
>
> ? ? ? ? exp(coef) ?exp(-coef) ? lower .95 ? ?upper .95
> ?y1 ? ? ?0.9762 ? ? 1.0244 ? ? ? 0.9703 ? ? ? ? 0.9821
> x2 ? ? ?1.0368 ? ? ?0.9645 ? ? ? 0.8796 ? ? ? ? 1.2222
>
>
> Thanks in advance
>