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st: problem with shared frailty cox model


From   "Fischer, Marcus" <mafische@mcw.edu>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: problem with shared frailty cox model
Date   Mon, 17 May 2004 12:07:30 -0500

I tried the shared frailty option in a cox proportional hazard model to account for the within-family correlation of my pedigree data.
After several hours (!!!) I got a convergence error when estimating the frailty variance. 
This just happened in a larger dataset (for example in 1500 individuals from 600 families, 1-4 members within a family); in a smaller subset it's working fine. Is it a memory problem ? Are there any requirements for the coding of the shared frailty variable ?

I would appreciate any suggestions very much since I have to analyze this (total) dataset very soon.

Thanks much,
Marcus



I believe that the standard approach is to use a share
frailty model. This can be done using -stcox-'s
-share()- option.

Best,
Ricardo.

--- "Fischer, Marcus" <mafische@mcw.edu> wrote:
> Hi,
> 
> I wish to evaluate associations between prospective
> disease risk and one or more genetic or
> environmental covariates, using data from families
> ascertained because of the disease statuses of some
> of their members. The population consists of
> nonoverlapping families each containing one or more
> individuals. Both disease occurences and covariates
> may be correlated within families.
> Is it possible to account for the within-family
> correlation in a cox proportional hazard model ? If
> so, how ?
> Can I just use the cluster(family-identifier) option
> to work with the robust variance-covariance matrix ?
> 
> Thanks for your help.
> Marcus



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