Dear users,

In a study with recurrent events: 
My objective is to get estimates of survival (obtained through a Cox model) by rank of recurrence and by treatment group.
With the following code (corresponding to a model with a global effect of the treatment=rx), I get no error and manage to obtain what I want : 
data<-(bladder)
model1<-coxph(Surv(stop,event)~rx+strata(enum)+cluster(id),data=bladder)
data1<-data.frame(rx=1)
survfit(model1,newdata=data1)

But with the model with strata by treatment interaction (corresponding to a model with an effect of the treatment by rank), I get the following error:
model2<-coxph(Surv(stop,event)~rx*strata(enum)+cluster(id),data=bladder)

data1<-data.frame(rx=1)

survfit(model2,newdata=data1)
Erreur dans strata(enum) : objet "enum" non trouvé =>error in strata(enum) : object "enum" not found

Would you have any idea to help me?

Thanks in advance,

Eva




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