survcomp (version 1.22.0)

cindex.comp.meta: Function to compare two concordance indices

Description

This function compares two lists of concordance indices computed from the same survival data by using the function concordance.index. The statistical test is a Student t test for dependent samples.

Usage

cindex.comp.meta(list.cindex1, list.cindex2, hetero = FALSE)

Arguments

list.cindex1

first list of concordance indices as returned by the concordance.index function.

list.cindex2

second list of concordance indices as returned by the concordance.index function.

hetero

if TRUE, a random effect model is use to compute the meta-estimators. Otherwise a fixed effect model is used.

Value

p.value

p-value from the Student t test for the comparison cindex1 > cindex2.

cindex1

meta-estimator of the first concordance index.

cindex2

meta-estimator of the second concordance index.

Details

In meta-analysis, we estimate the statistic of interest in several independent datasets. It results a list of estimates such as list of concordance indices. The two lists of concordance indices must be computed from the same samples (and corresponding survival data). The function computes a meta-estimator for the correlations between the two scores and uses a Student t test for dependent samples.

References

Cochrane, W. G. (1954) "The combination of estimates from different experiments", Biometrics, 10, pages 101--129.

Haibe-Kains, B. and Desmedt, C. and Sotiriou, C. and Bontempi, G. (2008) "A comparative study of survival models for breast cancer prognostication based on microarray data: does a single gene beat them all?", Bioinformatics, 24, 19, pages 2200--2208.

See Also

concordance.index.

Examples

#first dataset
set.seed(12345)
age <- rnorm(100, 50, 10)
size <- rexp(100,1)
stime <- rexp(100)
cens <- runif(100,.5,2)
sevent <- as.numeric(stime <= cens)
stime <- pmin(stime, cens)
c1.1 <- concordance.index(x=age, surv.time=stime, surv.event=sevent,
  method="noether")
c2.1 <- concordance.index(x=size, surv.time=stime, surv.event=sevent,
  method="noether")
#second dataset
set.seed(54321)
age <- rnorm(110, 53, 10)
size <- rexp(110,1.1)
stime <- rexp(110)
cens <- runif(110,.55,2)
sevent <- as.numeric(stime <= cens)
stime <- pmin(stime, cens)
c1.2 <- concordance.index(x=age, surv.time=stime, surv.event=sevent,
  method="noether")
c2.2 <- concordance.index(x=size, surv.time=stime, surv.event=sevent,
  method="noether")
cindex.comp.meta(list.cindex1=list("cindex.age1"=c1.1, "cindex.age2"=c1.2),
  list.cindex2=list("cindex.size1"=c2.1, "cindex.size2"=c2.2))