hazard.ratio.plot

0th

Percentile

Hazard Ratio Plot

The hazard.ratio.plot function repeatedly estimates Cox regression coefficients and confidence limits within time intervals. The log hazard ratios are plotted against the mean failure/censoring time within the interval. Unless times is specified, the number of time intervals will be $\max(round(d/e),2)$, where $d$ is the total number of events in the sample. Efron's likelihood is used for estimating Cox regression coefficients (using coxph.fit). In the case of tied failure times, some intervals may have a point in common.

Keywords
survival
Usage
hazard.ratio.plot(x, Srv, which, times=, e=30, subset,
                  conf.int=.95, legendloc=NULL, smooth=TRUE, pr=FALSE, pl=TRUE,
                  add=FALSE, ylim, cex=.5, xlab="t", ylab, antilog=FALSE, ...)
Arguments
x
a vector or matrix of predictors
Srv
a Surv object
which
a vector of column numbers of x for which to estimate hazard ratios across time and make plots. The default is to do so for all predictors. Whenever one predictor is displayed, all other predictors in the x matrix are adjusted f
times
optional vector of time interval endpoints. Example: times=c(1,2,3) uses intervals [0,1), [1,2), [2,3), [3+). If times is omitted, uses intervals containing e events
e
number of events per time interval if times not given
subset
vector used for subsetting the entire analysis, e.g. subset=sex=="female"
conf.int
confidence interval coverage
legendloc
location for legend. Omit to use mouse, "none" for none, "ll" for lower left of graph, or actual x and y coordinates (e.g. c(2,3))
smooth
also plot the super--smoothed version of the log hazard ratios
pr
defaults to FALSE to suppress printing of individual Cox fits
pl
defaults to TRUE to plot results
add
add this plot to an already existing plot
ylim
vector of y-axis limits. Default is computed to include confidence bands.
cex
character size for legend information, default is 0.5
xlab
label for x-axis, default is "t"
ylab
label for y-axis, default is "Log Hazard Ratio" or "Hazard Ratio", depending on antilog.
antilog
default is FALSE. Set to TRUE to plot anti-log, i.e., hazard ratio.
...
optional graphical parameters
See Also

cox.zph, residuals.cph, coxph.fit, cph, coxph, Surv

Aliases
  • hazard.ratio.plot
Examples
n <- 500
set.seed(1)
age <- 50 + 12*rnorm(n)
cens <- 15*runif(n)
h <- .02*exp(.04*(age-50))
d.time <- -log(runif(n))/h
label(d.time) <- 'Follow-up Time'
e <- ifelse(d.time <= cens,1,0)
d.time <- pmin(d.time, cens)
units(d.time) <- "Year"
hazard.ratio.plot(age, Surv(d.time,e), e=20, legendloc='ll')
Documentation reproduced from package rms, version 2.0-2, License: GPL (>= 2)

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