lines.survfit {survival}  R Documentation 
Often used to add the expected survival curve(s) to a KaplanMeier plot
generated with plot.survfit
.
## S3 method for class 'survfit': lines(x, type="s", mark=3, col=1, lty=1, lwd=1, mark.time=TRUE , xscale=1, firstx=0, firsty=1, xmax, fun, conf.int=FALSE, ...) ## S3 method for class 'survfit': points(x, ...)
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.

mark 
vectors giving the mark symbol, color, line type and line width for the added curves. 
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.

xscale 
a number used to divide the x values. If time was originally in days, a value of 365.24 would give a plotted scale in years. 
firstx,firsty 
the starting point for the survival curves. If either of these is set to
NA or <blank> the plot will start at the first time point of the curve.

col,lty,lwd,... 
passed to lines 
xmax 
the maximum horizontal plot coordinate.
This shortens the curve before plotting it, so unlike using the
xlim graphical parameter, warning messages about out of bounds points are
not generated.

fun 
an arbitrary function defining a transformation of the survival curve.
For example fun=log is an alternative way to draw a logsurvival 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) =1y),
"cumhaz" plots the cumulative hazard function (f(y) = log(y))
and "cloglog" creates a complementary loglog survival plot
(f(y) = log(log(y)) along with log scale for the xaxis). 
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 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.
one or more curves are added to the current plot.
lines
, par
, plot.survfit
, survfit
, survexp
.
fit < survfit(Surv(time, status) ~ sex, pbc,subset=1:312) plot(fit, mark.time=FALSE, xscale=365.24, xlab='Years', ylab='Survival') lines(fit[1], lwd=2, xscale=365.24) #darken the first curve and add marks # add expected survival curves for the two groups, # based on the US census data tdata < data.frame(age=pbc$age*365.24, sex=pbc$sex +1, year= rep(mdy.date(1,1,1976), nrow(pbc))) tdata<tdata[1:312,] ## only the randomised people, with no missing data efit < survexp(~ sex+ratetable(sex=sex,age=age,year=year), data=tdata, ratetable=survexp.us, times=(0:24)*182) temp < lines(efit, lty=2, xscale=365.24, lwd=2:1) text(temp, c("Male", "Female"), adj= .1) #labels just past the ends title(main="Primary Biliary Cirrhosis, Observed and Expected")