R help - May 2012 - Hmisc improveProb() and PredictABEL reclassification () function and continuous NRI

Dear Sirs.

I am working with the  R packages Hmisc and PredictABEL to make NRI estimates
from my Cox models with and without a specific biomarker.
According to Pencina et al (Statistics in Medicine 2010, DOI: 0.1002/sim.4085 ),
a continuous/non-categorical NRI (NRI>0) is to be used when there are no
obvious reason to categorize risk, such as the risk of future cardiovascular
events in patients with established cardiovascular disease.

My question is therefore: Which value(s) are to be used in the calculation of
continuous NRI from the output in Hmisc or in PredictABEL? Does continuous NRI
equal total NRI in the output?



Yours sincerely

Gard Frodahl T. Svingen
PhD student
the University of Bergen
Bergen, Norway


	[[alternative HTML version deleted]]

If you type improveProb at the command line you'll see all the code, which
is
quite simple.  I'm glad you are not attempting to classify risk as this is
almost always futile.

Frank

Svingen, Gard Frodahl wrote
> 
> Dear Sirs.
> 
> I am working with the  R packages Hmisc and PredictABEL to make NRI
> estimates from my Cox models with and without a specific biomarker.
> According to Pencina et al (Statistics in Medicine 2010, DOI:
> 0.1002/sim.4085 ), a continuous/non-categorical NRI (NRI>0) is to be
used
> when there are no obvious reason to categorize risk, such as the risk of
> future cardiovascular events in patients with established cardiovascular
> disease.
> 
> My question is therefore: Which value(s) are to be used in the calculation
> of continuous NRI from the output in Hmisc or in PredictABEL? Does
> continuous NRI equal total NRI in the output?
> 
> 
> 
> Yours sincerely
> 
> Gard Frodahl T. Svingen
> PhD student
> the University of Bergen
> Bergen, Norway
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help@ mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 



-----
Frank Harrell
Department of Biostatistics, Vanderbilt University
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