R help - Dec 2010 - Help with time varying covariate-unfold function

Hello All,

 

I am trying to use the unfold function in RcmdrPlugin.survival library,
which converts the survival data with time varying covariates to the
counting process notation.  The problem is somehow, the event indicator
created is not correct.   

Below is the data, I am trying to convert:

 

CASE TRT FAILTIME FAILCENS SEX     AGE  IGG0 IGG28 IGG42  IGG84 IGG364 

26003   A  11.2033        2                1     43.9535    0    80    80
320     NA     

 

IGG0 to IGG364 are my time varying covariates and FAILCENS = 2 indicates
observed times. So, when I tried to use,

 

igg2.long<-unfold(igg.2[3,],time="FAILTIME",event="FAILCENS",cov=9:13,cov.na
mes="iggtitre"), I obtained the following output:

    start stop FAILCENS.time  CASE TRT FAILTIME FAILCENS SURVTIME SURVCENS
SEX

3.1     0    1             0 26003   A  11.2033        1  17.5441        1
1

3.2     1    2             0 26003   A  11.2033        1  17.5441        1
1

3.3     2    3             0 26003   A  11.2033        1  17.5441        1
1

3.4     3    4             0 26003   A  11.2033        1  17.5441        1
1

        AGE IGGrel iggtitre

3.1 43.9535     NA        0

3.2 43.9535     NA       80

3.3 43.9535     NA       80

3.4 43.9535     NA      320
>  
As it can be seen, this data was observed, but my censoring indicator
(FAILCENS.time) for the last start stop line should have been one, which is
not. 

 

Could somebody help me  with this problem? I did try using the Rossi data
also, which is an example in the unfold function.  Even there, the
arrest.time are all zero, even when the event happened.

 

Thanks a lot for your time.

 

Mathangi

 

 

 


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