# lines.survfit

##### Add Lines or Points to a Survival Plot

Often used to add the expected survival curve(s) to a Kaplan-Meier plot
generated with `plot.survfit`

.

- Keywords
- survival

##### Usage

```
# S3 method for survfit
lines(x, type="s", pch=3, col=1, lty=1,
lwd=1, cex=1, mark.time=FALSE,
fun, conf.int=FALSE,
conf.times, conf.cap=.005, conf.offset=.012,
conf.type = c("log", "log-log", "plain", "logit", "arcsin"),
mark, noplot="(s0)", cumhaz= FALSE, ...)
# S3 method for survexp
lines(x, type="l", ...)
# S3 method for survfit
points(x, fun, censor=FALSE, col=1, pch,
noplot="(s0)", cumhaz=FALSE, ...)
```

##### Arguments

- x
a survival object, generated from the

`survfit`

or`survexp`

functions.- type
the line type, as described in

`lines`

. The default is a step function for`survfit`

objects, and a connected line for`survexp`

objects. All other arguments for`lines.survexp`

are identical to those for`lines.survfit`

.- col, lty, lwd, cex
vectors giving the mark symbol, color, line type, line width and character size for the added curves. Of this set only color is applicable to

`points`

.- pch
plotting characters for points, in the style of

`matplot`

, i.e., either a single string of characters of which the first will be used for the first curve, etc; or a vector of characters or integers, one element per curve.- mark
a historical alias for

`pch`

- censor
should censoring times be displayed for the

`points`

function?- ...
other graphical parameters

- mark.time
controls the labeling of the curves. If

`FALSE`

, no labeling is done. If`TRUE`

, then curves are marked at each censoring time. If`mark.time`

is a numeric vector, then curves are marked at the specified time points.- fun
an arbitrary function defining a transformation of the survival curve. For example

`fun=log`

is an alternative way to draw a log-survival curve (but with the axis labeled with log(S) values). Four often used transformations can be specified with a character argument instead: "log" is the same as using the`log=T`

option, "event" plots cumulative events (f(y) = 1-y), "cumhaz" plots the cumulative hazard function (f(y) = -log(y)) and "cloglog" creates a complimentary log-log survival plot (f(y) = log(-log(y))) along with log scale for the x-axis.- conf.int
if

`TRUE`

, confidence bands for the curves are also plotted. If set to`"only"`

, then only the CI bands are plotted, and the curve itself is left off. This can be useful for fine control over the colors or line types of a plot. A numeric value, e.g.`conf.int = .90`

, can be used to- conf.times
optional vector of times at which to place a confidence bar on the curve(s). If present, these will be used instead of confidence bands.

- conf.cap
width of the horizontal cap on top of the confidence bars; only used if conf.times is used. A value of 1 is the width of the plot region.

- conf.offset
the offset for confidence bars, when there are multiple curves on the plot. A value of 1 is the width of the plot region. If this is a single number then each curve's bars are offset by this amount from the prior curve's bars, if it is a vector the values are used directly.

- conf.type
One of

`"plain"`

,`"log"`

(the default),`"log-log"`

,`"logit"`

, or`"none"`

. Only enough of the string to uniquely identify it is necessary. The first option causes confidence intervals not to be generated. The second causes the standard intervals`curve +- k *se(curve)`

, where k is determined from`conf.int`

. The log option calculates intervals based on the cumulative hazard or log(survival). The log-log option bases the intervals on the log hazard or log(-log(survival)), and the logit option on log(survival/(1-survival)).- noplot
for multi-state models, curves with this label will not be plotted. The default corresponds to an unspecified state.

- cumhaz
plot the cumulative hazard, rather than the survival or probability in state.

##### Details

When the `survfit`

function creates a multi-state survival curve
the resulting object has class `survfitms'. The only difference in
the plots is that that it defaults to a curve that goes from lower
left to upper right (starting at 0), where survival curves default
to starting at 1 and going down. All other options are identical.

##### Value

a list with components `x`

and `y`

, containing the coordinates of the
last point on each of the curves (but not of the confidence limits).
This may be useful for labeling.

##### Side Effects

one or more curves are added to the current plot.

##### See Also

`lines`

, `par`

, `plot.survfit`

, `survfit`

, `survexp`

.

##### Examples

```
# NOT RUN {
fit <- survfit(Surv(time, status==2) ~ sex, pbc,subset=1:312)
plot(fit, mark.time=FALSE, xscale=365.25,
xlab='Years', ylab='Survival')
lines(fit[1], lwd=2) #darken the first curve and add marks
# Add expected survival curves for the two groups,
# based on the US census data
# The data set does not have entry date, use the midpoint of the study
efit <- survexp(~sex, data=pbc, times= (0:24)*182, ratetable=survexp.us,
rmap=list(sex=sex, age=age*365.35, year=as.Date('1979/01/01')))
temp <- lines(efit, lty=2, lwd=2:1)
text(temp, c("Male", "Female"), adj= -.1) #labels just past the ends
title(main="Primary Biliary Cirrhosis, Observed and Expected")
# }
```

*Documentation reproduced from package survival, version 3.1-8, License: LGPL (>= 2)*