# [R] Extracting approximate Wald test (Chisq) from coxph(..frailty)

Paul Artes paul_h_artes at yahoo.co.uk
Tue Apr 17 18:02:29 CEST 2007

```Assign the output of coxph to some object, and use the \$ extractor function
to obtain what you need.

ie:
rtfm <- coxph(formula = Surv(time, status) ~ age + sex +  disease +
frailty(id, dist = "gauss"), data = kidney)
Age <- coef(rtfm)["age"]
OR
Sex <- rtfm\$coef["sex"]

Hope this helps.

Paul

>
> Dear List,
>
> How do I extract the approximate Wald test for the
> frailty (in the following example 17.89 value)?
>
> What about the P-values, other Chisq, DF, se(coef) and
> se2? How can they be extracted?
>
> ######################################################>
> kfitm1
> Call:
> coxph(formula = Surv(time, status) ~ age + sex +
> disease + frailty(id,
>     dist = "gauss"), data = kidney)
>
>                           coef     se(coef)
> age                        0.00489 0.0150
> sex                       -1.69703 0.4609
> diseaseGN                  0.17980 0.5447
> diseaseAN                  0.39283 0.5447
> diseasePKD                -1.13630 0.8250
> frailty(id, dist = "gauss
>                           se2    Chisq DF
> age                       0.0106  0.11  1.0
> sex                       0.3617 13.56  1.0
> diseaseGN                 0.3927  0.11  1.0
> diseaseAN                 0.3982  0.52  1.0
> diseasePKD                0.6173  1.90  1.0
> frailty(id, dist = "gauss        17.89 12.1
>                           p
> age                       0.74000
> sex                       0.00023
> diseaseGN                 0.74000
> diseaseAN                 0.47000
> diseasePKD                0.17000
> frailty(id, dist = "gauss 0.12000
>
> Iterations: 6 outer, 30 Newton-Raphson
>      Variance of random effect= 0.493
> Degrees of freedom for terms=  0.5  0.6  1.7 12.1
> Likelihood ratio test=47.5  on 14.9 df, p=2.82e-05  n=
> 76
>
> ######################################################
>
> Thank you for your time.
>
> wildscop at yahoo dot com
> Institute of Statistical Research and Training
> University of Dhaka
>
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