frailtypack (version 2.5.1)

SurvIC: Create a survival object for interval censoring and possibly left truncated data

Description

This is a function used in case of interval-censoring as a response variable in a model formula only for Cox proportional hazard or shared frailty model. Sometimes, an unobserved event might occur in a time interval [L,U]. RecurrentAG argument gets invalid with the use of SurvIC. Time dependant variables are not allowed.

Usage

SurvIC(t0, lower, upper, event)

Arguments

lower

Starting time of the interval for interval-censored data. Time of right-censoring instead.

upper

Ending time of the interval for interval-censored data. For right-censored data, lower and upper time must be equal (for numerical reason).

event

Status indicator 0=right-censored, 1=interval-censored

t0

Truncation time for left truncated data only. To be ignored otherwise.

Details

Typical usages are SurvIC(lower,upper,event) or SurvIC(t0,lower,upper,event)

Examples

data(bcos)
bcos$event <- ifelse(bcos$left!=bcos$right,1,0)

###---  Cox proportional hazard model with interval censoring ---###

cox.ic <- frailtyPenal(SurvIC(left,right,event)~treatment,
data=bcos,Frailty=FALSE,n.knots=8,kappa1=10000)

###---  Shared model with interval censoring ---###

bcos$group <- c(rep(1:20,4),1:14)

sha.ic <- frailtyPenal(SurvIC(left,right,event)~cluster(group)+
treatment,data=bcos,Frailty=TRUE,n.knots=8,kappa1=10000)