ahrAJ: ahrAJ

In mbrueckner/AHR: Estimation and Testing of Average Hazard Ratios

Description

Estimate average hazard ratios from k independent samples based on the Aalen-Johansen estimator of the empirical transition probabilities (NOTE: variance estimation not yet implemented)

Usage

ahrAJ(L, target, states, transitions, censoring, data, null.theta = NULL,
  contrast = NULL, multi.test = FALSE, cov = FALSE, bootstrap = 0)

Arguments

L	time-limit specifying time-interval [0,L] over which average hazard ratios will be calculated
target	string specifying the target transition, for which the Aalen-Johansen estimator is to be calculated
states	list of state names
transitions	matrix of possible transitions
censoring	name of censoring 'state'
data	data frame containing variables id, time, from, to (see etm) and Trt (factor giving treatment groups)
null.theta	vector specifying the null hypothesis for the average hazard ratios
contrast	vector of contrasts to test H_0: contrast * (theta - null.theta) = 0
multi.test	calculate multivariate test statistic if TRUE
cov	if TRUE calculate covariance matrix estimator (direct)
bootstrap	number of bootstrap samples to draw for variance estimation (default: 0 = no bootstrap, direct variance estimation). This parameter is ignored if cov=TRUE

Value

An object of class '"ahr"'

References

J.~D. Kalbfleisch and R.~L. Prentice. Estimation of the average hazard ratio. Biometrika, 68(1):105–112, Apr. 1981.

See Also

aj

Examples

## competing risks
Trt <- factor(rep(c(0,1), c(100, 100)))
T <- c(rexp(100, 1), rexp(100, 2))
C <- c(rexp(100, 1), rexp(100, 2))
r <- c(rbinom(100, 2, 0.5), rbinom(100, 2, 0.4))
r[(r == 0) | (T > C)] <- "cens"
data <- data.frame(id=1:200, time=pmin(T,C), from=rep(0, 200), to=r, Trt=Trt)
tra <- matrix(FALSE, nrow=3, ncol=3)
tra[1, 2:3] <- TRUE
# estimate average subdistribution hazard ratio up to L=2 for event type 1
fit <- ahrAJ(2, target="0 1", states=c("0", "1", "2"), transitions=tra, censoring="cens",
             data=data, cov=TRUE)
fit

mbrueckner/AHR documentation built on May 22, 2019, 12:57 p.m.