[R] Hazard ratio

[David Winsemius]

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