extract_hazard() R function from [success]

Extract (inverse) cumulative baseline hazard from Cox PH model

Extracts a function which returns the (inverse) cumulative baseline hazard from a coxph() call.


extract_hazard(coxphmod)

Arguments

coxphmod: A call to coxph().

Returns

A list containing:

cbaseh: A function which returns the cumulative baseline hazard at specified time;
inv_cbaseh: A function which returns the inverse cumulative baseline hazard at specified time.
max_time: maximal time at which cbaseh is known;
max_haz: value of maximal hazard (at maximum time).

Details

The baseline hazard is extracted from the coxph()

call using the basehaz() function. The baseline hazard function is then smoothed using approxfun() to obtain the linear interpolant. If required, the inverse baseline hazard is determined using root linear interpolation. For this, a function written by Zheyuan Li (see references) is used.

Examples


require(survival)
exprfit <- as.formula("Surv(survtime, censorid) ~ age + sex + BMI")
tcoxmod <- coxph(exprfit, data= surgerydat)
tcox_hazard_fcts <- extract_hazard(tcoxmod)