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.

```
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, …)
```

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 for (with a separate adjustment form for each time interval).

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

# NOT RUN { 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') # }