Hi R-users,
I have a data set with a particular type of interval-censored data: right
and left censored data, but no other type of interval censoring. I need to
fit a model with covariates to evaluate the influence of them on the
survival time.
First: I use Surv of library(survival) to create my survival object. I have
two possibilities:
Surv(c(1,1,NA,3),c(1,NA,2,3),type="interval2")
# 1 1+ 2- 3 , I do not [a,b] in
any case.
Surv(c(1,1,2,3),c(1,2,2,3),c(1,0,2,1),type="interval")
1 1+ 2- 3
Second:Given that coxph is not valid for interval-censored type of data, I
use survreg with covariates.
survreg(Surv(c(1,1,NA,3),c(1,NA,2,3),type="interval2") ~covariate)
Third: Now I need to fit a model with time-dependent covariates, but I only
find examples of how to include time-dependent covariates when using coxph
without left censoring (data=Rossi.txt, Jhon Fox), and therfore the "event"
in Surv is 0 until the event occurrs:
http://cran.r-project.org/doc/contrib/Fox-Companion/appendix-cox-regression.pdf
My question is: How could I fit a survival model that include right-left
censoring and time-dependent covariates?
Thanks a lot in advance,
Berta.
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