DTR (version 1.7)

PHfit: Function for fitting a generalized proportional hazards model

Description

The function fits a generalized proportional hazards model as proposed in Tang and Wahed (2011).

Usage

PHfit(data, covar=NULL)

Arguments

data

a data frame (X, TR, R, Z, U, delta, ...) representing the data from a two-stage randomization design with therapies A1 and A2 available at the first stage, and B1 and B2 available at the second stage. X: first-stage indicator, X=0 if assigned to A1, and

covar

covariate(s) to be adjusted in the model. The default (covar=NULL) fits a model without any covariates

Value

• The function returns an object of class coxph. See coxph.object for details.

Details

In sequentially randomized designs, there could be more than two therapies available at each stage. For simplicity, and to maintain similarity to the most common sequentially randomized clinical trials, a two-stage randomization design allowing two treatment options at each stage is used in the current version of the package. In detail, patients are initially randomized to either A1 or A2 at the first stage. Based on their response status, they are then randomized to either B1 or B2 at the second stage. Therefore, there are a total of four DTRs: A1B1, A1B2, A2B1, and A2B2.

References

Tang X, Wahed AS: Comparison of treatment regimes with adjustment for auxiliary variables. Journal of Applied Statistics 38(12):2925-2938, 2011

See Also

simPHdata, coxph.object

Examples

data("PHdata")
f <- PHfit(data=PHdata, covar="V")
summary(f)