xsect function

Make a cross-section of multi-state data at a given time point

Given a dataset in long format, for instance generated by msprep, this function takes a cross-section at a given time point, to list the subjects under observation (at risk) at that time point and the states currently occupied.

xsect(msdata, xtime = 0)

Arguments

• msdata: An object of class "msdata", such as output by msprep
• xtime: The time point at which the intersection is to be made

Returns

A list containing idstate, a data frame containing id's and state, the number of the state currently occupied; atrisk, the number at risk, and prop, a table counting how many of those at risk occupy which state.

Details

It is possible that subjects have moved to one of the absorbing states prior to xtime; this is NOT taken into account. The function xsect

only concerns subjects currently (at time) at risk.

Examples

tmat <- trans.illdeath(names=c("Tx","PR","RelDeath"))
data(ebmt3) # data from Section 4 of Putter, Fiocco & Geskus (2007)
msebmt <- msprep(time=c(NA,"prtime","rfstime"),status=c(NA,"prstat","rfsstat"),
                data=ebmt3,trans=tmat)
# At the start everyone is in state 1 (default xtime=0 is used)
xsect(msebmt)
# At 5 years
xsect(msebmt, xtime=1826)

Author(s)

Hein Putter H.Putter@lumc.nl