jointplot: Joint plot of longitudinal and survival data

Description

This function views the longitudinal profile of each unit with the last longitudinal measurement prior to event-time (censored or not) taken as the end-point, referred to as time zero. In doing so, the shape of the profile prior to event-time can be inspected. This can be done over a user-specified number of time units.

Usage

jointplot(object, Y.col, Cens.col, lag, split = TRUE, col1, col2, 
          xlab, ylab, gp1lab, gp2lab, smooth, 
          mean.profile = FALSE, mcol1, mcol2)

Arguments

object

Name of the jointdata object

Y.col

An element of class character identifying the longitudinal response part of the jointdata object.

Cens.col

An element of class character identifying the survival status or censoring indicator part of the jointdata object.

lag

Argument which specifies how many units in time we look back through. Defaults to the maximum observation time across all units.

split

TRUE/FALSE argument which allows the profiles of units which fail and those which are censored to be viewed in separate panels of the same graph. This is the default option. Using

col1

argument to choose the colour for the profiles of the censored units.

col2

argument to choose the colour for the profiles of the failed units.

xlab

An element of class character indicating the title for the x-axis.

ylab

An element of class character indicating the title for the x-axis.

gp1lab

An element of class character for the group corresponding to a censoring indicator of zero. Typically, the censored group.

gp2lab

An element of class character for the group corresponding to a censoring indicator of one. Typically, the group experiencing the event of interest.

smooth

the smoother span. This gives the proportion of points in the plot which influence the smooth at each value. Defaults to a value of 2/3. Larger values give more smoothness. See lowessfor further details.

mean.profile

draw mean profiles if TRUE. Only applies to the split = TRUE case.

mcol1

argument to choose the colour for the mean profile of the units with a censoring indicator of zero.

mcol2

argument to choose the colour for the mean profile of the units with a censoring indicator of one.

Details

The function tailors the xyplot function in lattice to produce a representation of joint data with longitudinal and survival components.

References

Wulfsohn, M. S. and Tsiatis, A. A. (1997) A Joint Model for Survival and Longitudinal Data Measured with Error, Biometrics, 53, 330-339.

Examples

Run this code

data(heart.valve)
heart.surv <- UniqueVariables(heart.valve, 
                              var.col = c("fuyrs", "status"),
                              id.col = "num")
heart.long <- heart.valve[,c("num", "time", "log.lvmi")]
heart.cov <- UniqueVariables(heart.valve, 
                             c("age", "sex"), 
                             id.col = "num")
heart.valve.jd <- jointdata(longitudinal = heart.long, 
                            baseline = heart.cov, 
                            survival = heart.surv,
                            id.col = "num",
                            time.col = "time")
jointplot(heart.valve.jd, Y.col = "log.lvmi", 
          Cens.col = "status", lag = 5)