nrAtRisk {survCurve}

Adds number at risk of a survival model to a plot.

Description

This function adds the number at risk of one group (strata) of a survfit object to an existing plot. If label is specified, it draws a label for the group right to the number at risks. If any elements of the "flag" is specified, it also draws a small identifier, with which the corresponding curves / confidence intervals of the plot can be identified near to the label.

Usage

nrAtRisk(
  x,
  group,
  ypos = 0.08,
  times,
  interval.times,
  zero.adjust = TRUE,
  zero.value,
  font.text = 1,
  cex.text = 1,
  col.text = "black",
  cex.nr,
  col.nr,
  font.nr,
  label,
  xpos.lab,
  cex.lab,
  col.lab,
  font.lab,
  lty.flag,
  lwd.flag,
  bgcol.flag,
  lncol.flag,
  xlim.flag
)

Arguments

x

A survfit (survival-package) or a Cuminc (mstate-package) object.

group

The number of the group (=strata) of which the confidence interval should be plotted. If the survfit-object has only one strata, this argument can be omitted.

ypos

A numeric value for the position at the y-axis.

times

An optional vector of numeric values specifying at which times (x-axis) the number at risk are calculated and plotted. If not specified, the defaults depends on "interval.times" value if available, or the size of the plot.

interval.times

An optional numeric value which specifies the interval at which the number at risk values are plotted. Is overwritten by times. If not specified, the value depends on the size of the plot.

zero.adjust

A logical value. If true, the number at risk at time 0 is not plotted at the precise position, but slightly adjusted to the left to prevent the value to be cut-off by the plot margins. Also, the value at x=0 is plotted if true. Default is TRUE.

zero.value

A numeric value or string that overwrites the nr at risk value at x=0 if specified (only if zero.adjust is TRUE).

font.text

Font of the text (nr at risk and label). Default is 1.

cex.text

Font-size of the text (nr at risk and label). Default is 1.

col.text

Colour of the text (nr at risk and label). Default is "black".

cex.nr

Overwrites cex.text for the number-part.

col.nr

Overwrites col.text for the number-part.

font.nr

Overwrites font.text for the number-part.

label

String for the group name.

xpos.lab

x-position of the label, default is near the right border of the plot.

cex.lab

Overwrites cex.text for the label-part.

col.lab

Overwrites col.text for the label-part.

font.lab

Overwrites font.text for the label-part.

lty.flag

Line-type of the flag. Value is 1 if not specified.

lwd.flag

Line-wide of the flag. Value is 1 if not specified.

bgcol.flag

Background-color of the flag (corresponding to the color of the confidence interval in the plot). No color if not value is specified.

lncol.flag

color of the line of the flag. Default is "black".

xlim.flag

Vector with two values, defining the beginning and end of the flag on the x-axis. Default depends on the size of the plot.

Value

Draws the number at risk to an existing plot.

Examples

  require(survival)
  aml_model <- with(aml, survfit(Surv(time, status)~x))
  col1 <- adjustcolor("red",0.2); col2 <- adjustcolor("blue",0.2)
  survPlot(xmax=50, space.nrAtRisk=0.32)
  confIntArea(aml_model, col=col1, group=1)
  confIntArea(aml_model, col=col2, group=2)
  survCurve(aml_model, group=1)
  survCurve(aml_model, group=2, lty=2)
  nrAtRisk(aml_model, group=1, y=-0.17, bgcol.flag=col1, label="maintain")
  nrAtRisk(aml_model, group=2, y=-0.24, bgcol.flag=col2, lty.flag=2, label="non-maint.")