[R] How to estimate a hazard ratio using an external hazard function

[Montse Rué]

Hi,

I would like to compare the hazard functions of two samples using the  
Cox proportional hazards model. For sample 1 I have individual time-to- 
event data. For sample 2 I don't have individual data, but grouped  
data that allows to obtain a hazard function.

I am wondering if there is an R function that allows to obtain a  
hazard ratio of the two hazard funtions (under the proportionality  
assumption) taking into account the censoring of the data?

I am aware of survexp and survdiff functions, but I am not sure if  
that is the best way to do what I need.

Any help will be highly appreciated.

Montse Rue
Department of Basic Medical Sciences
University of Lleida (Spain)