The coding for an AFT model with time-dependent covariates will be very hard, and I don't know of anyone who has done it. (But I don't keep watch of other survival packages, so something might be there). In a Cox model, a subject's risk depends only on the current value of his/her covariates; in an AFT model the risk depends on the entire covariate history. (My 'accelerated age' is the sum of all the extra years I have ever gained). Coding this is not theoretically complex, but would be a pain-in-the-rear amount of bookkeeping. Terry Therneau
AFT-model with time-dependent covariates
2 messages · Terry Therneau, Spencer Graves
To see what's available in other packages, try the following:
library(RSiteSearch)
AFT <- RSiteSearch.function('AFT model')
summary(AFT) # 24 help files found in 8 different packages
HTML(AFT) # opens a table with 24 rows in a web browser.
There may be nothing here that will help you, but this provides a
quick overview of what's available. If this doesn't find what you want,
it either has not been contributed or its help page does not use the
phrase "AFT model".
Hope this helps.
Spencer Graves
Terry Therneau wrote:
The coding for an AFT model with time-dependent covariates will be very hard, and I don't know of anyone who has done it. (But I don't keep watch of other survival packages, so something might be there). In a Cox model, a subject's risk depends only on the current value of his/her covariates; in an AFT model the risk depends on the entire covariate history. (My 'accelerated age' is the sum of all the extra years I have ever gained). Coding this is not theoretically complex, but would be a pain-in-the-rear amount of bookkeeping. Terry Therneau
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