Good afternoon,
I am currently trying to do some work on survival analysis.
- I hope to seek your advice re: 2 questions (1 general and 1 specific)
(1) I'm trying to do a stratified Cox analysis and subsequently
plot(survfit(object)). It seems to work for some strata, but not for
others.
I have tumor grade, which is a range of 1 - 4.
When I divide this range of 1:4 into 2 groups, it works fine for
strata(grade>2) and strata(grade > 3). However, if I do a
strata(grade>1), there is an error when I do a survfit( <coxph object>
)
Call: survfit.coxph(object = s)
Error in print.survfit(structure(list(n = as.integer(46), time = c(22, :
length of dimnames [1] not equal to array extent
(2) As a general question, is it possible to distinguish between
confounding and interaction in the Cox proportional hazards model?
Thanks!
Min-Han
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