Thanks to David Winsemius for the replay. i use the latest update of
Hmisc package and I try as reported in the example:
set.seed(1)
library(survival)
x1 <- rnorm(400)
x2 <- x1 + rnorm(400)
d.time <- rexp(400) + (x1 - min(x1))
cens <- runif(400,.5,2)
death <- d.time <= cens
d.time <- pmin(d.time, cens)
rcorrp.cens(x1, x2, Surv(d.time, death))
but to me it appears that NRI and IDi are not reported in the results:
Dxy S.D. x1 more concordant x2 more concordant
-8.212107e-02 1.370738e-01 4.589395e-01 5.410605e-01
n missing uncensored Relevant Pairs
4.000000e+02 0.000000e+00 1.100000e+01 4.262000e+03
Uncertain C X1 C X2 Dxy X1
1.553380e+05 9.920225e-01 9.258564e-01 9.840450e-01
Dxy X2
8.517128e-01
but only after:
#rcorrp.cens(x1, x2, y) ## no censoring
set.seed(1)
x1 <- runif(1000)
x2 <- runif(1000)
y <- sample(0:1, 1000, TRUE)
rcorrp.cens(x1, x2, y)
improveProb(x1, x2, y)
thus censoring not allowed. Or I'm in error?
Many thanks
David Winsemius <dwinsem...@comcast.net> ha scritto:
On Nov 7, 2012, at 6:54 AM, petre...@unina.it wrote:
Dear all,
I am interested to evaluate reclassification using net
reclassification improvement and Integrated Discrimination Index IDI after
survival analysis (Cox proportional hazards using stcox). I search a R
package or a R code that specifically addresses the categorical NRI for
time-to-event data in the presence of censored observation and, if
possible, at different follow-up time points.
I know that the ‘PredictABEL’ Package contains functions for NRI and IDI
calculation but it is unclear for me if it allows censored observation.
Package ‘survIDINRI’ calculates only continuous NRI and the function of
Package ‘Hmisc’[#rcorrp.cens(x1, x2, y) ##] is only for no censored
observations.
???. Doesn't its name , 'rcorrp.cens' suggest otherwise? Not to
mention its description int the Hmisc Index: "Rank Correlation for
Paired Predictors with a Possibly Censored Response, and Integrated
Discrimination Index". rcoop.cens is a fairly recent addition to
Hmisc and I am looking at Hmisc version 3.10-1. If you are looking
at a version that is a couple of years old, you may be seeing
something different. The argument list you list looks like the one
for improveProb(), which does not appear to handle censoring. The
rcorrp.cens argument list is:
rcorrp.cens(x1, x2, S, outx=FALSE, method=1)
And the "S" object is a Surv-object.
Many thanks.
Sincerely,
Mario Petretta
Dpt. Internal Medicine, Cardiology and Heart Surgery
Naples University Federico II - Italy
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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David Winsemius, MD
Alameda, CA, USA
Mario Petretta
Dipartimento di Medicina Clinica Scienze Cardiovascolari e Immunologiche
Facolt� di Medicina e Chirurgia
Universit� di Napoli Federico II
081 - 7462233
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
