cif {surv2sample}R Documentation

Estimates of Cumulative Incidence Functions for Competing Risks Data

Description

Compute estimates of cumulative incidence functions for one or more samples of censored data with several competing risks (types of failure).

Usage

cif(x, group)

Arguments

x an object of class "Survcomp".
group a vector giving for each observation the group to which the observation belongs. If there are K samples, group may only contain values 1,...,K. If group is missing, observations are assumed to be one sample.

Details

The cumulative incidence function F(t,j) is defined as the probability of failure by time t from a particular cause j in the presence of other competing risks 1,...,j-1,j+1,...,J, that is, F(t,j)=P(T<=t, e=j), where T is the failure time and e is the failure cause.

The function cif estimates cumulative incidence functions for all causes and all groups.

Value

cif returns a list of class "cif" with the following components:

[[k]] a list containing estimates for the kth sample. It has components time (sorted times in the group k), surv (the Kaplan–Meier estimate of the overall survival in this group), and f, which is a matrix containing estimates of cumulative incidence functions for the kth sample. The jth column of f is the cumulative incidence function for the cause j.
time the vector of sorted times.
event the vector of corresponding event types.
group the vector of corresponding group indicators.
ncauses the number of causes present in the data.
ngroups the number of samples.

Author(s)

David Kraus (http://www.davidkraus.net/)

References

Klein, J. P. and Moeschberger, M. L. (2003) Survival Analysis. Techniques for Censored and Truncated Data. Springer, New York. (Section 2.7)

See Also

Survcomp, plot.cif

Examples

## bone marrow transplant data
data(bmt1)

print(a <- cif(Survcomp(bmt1$time, bmt1$event), bmt1$donor))
str(a)

## several first times and cifs for group 1 (HLA-identical
## sibling donors)
head(cbind(a[[1]]$time, a[[1]]$f))
## several last times and cifs for group 2 (HLA-matched
## unrelated donors)
tail(cbind(a[[2]]$time, a[[2]]$f))

## plot aggregate cumulative incidence functions for each
## donor type to see probabilities within groups
plot(a)

[Package surv2sample version 0.1-2 Index]