DTR (version 1.7)

contrast_ph: Function to compare dynamic treatment regimes (DTRs) after adjustment for covariates

Description

This function compares the survival distributions (i.e. hazard functions) of dynamic treatment regimes (DTRs) from sequentially randomized clinical trials after adjustment for covariates as proposed in Tang and Wahed (2011).

Usage

contrast_ph(fit)

Arguments

fit

the result of a call to the PHfit function

Value

The function returns a data frame with four columns: H0, test statistic, df, and p.

H0

the null hypotheses being tested, for example, H0 (t=3) if the comparisons are made at t=3

test statistic

the calculated chi-square test statistic

df

the degree of freedom

p

the resulting p-value

Details

Four different comparisons are performed: 1) An overall comparison H0: A1B1=A1B2=A2B1=A2B2 2) First-stage comparison H0: A1=A2 3) Second-stage comparison H0: B1=B2 4) Pairwise comparisons including H0: A1B1=A1B2, H0: A1B1=A2B1, H0: A1B1=A2B2, H0: A1B2=A2B1, H0: A1B2=A2B2, and H0: A2B1=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

PHfit, coxph.object

Examples

## Not run: 
# data("PHdata")
# f <- PHfit(data=PHdata, covar="V")
# contrast_ph(f)## End(Not run)