[R] AFT model time-dependent with weibull distribution

[Göran Broström]

On Fri, Aug 19, 2011 at 2:55 PM, javier palacios <xpfenech at gmail.com> wrote:
> Dear R-community,
>
> I have tried to estimate an accelerated failure time(AFT) and proportional
> hazard (PH) parametric survival model with time-independent  and
> time-dependent covariates. For that purpose, I have used the eha package.
>
>
> Please, consider this example:
>
> weibullph <- phreg(Surv(sta,time,S) ~ TDC1 + TIC1, dist="weibull",
> data.frame=Data)
>
> weibullaft<-aftreg(Surv(sta,time,S) ~ TDC1 + TIC1, dist="weibull",
> data.frame=Data)
>
> ## aftreg gives error when I add ID argument...
>
> Error in aftreg.fit(X, Y, dist, strats, offset, init, shape, id, control,  :
>  Overlapping intervals for id  2

Does not happen to me.

>
> >From help(aftreg): id If there are more than one spell per individual, it is
> essential to keep spells together by the id argument. This allows for
> time-varying covariates.
>
>
> data table:
>
> Data
>   S sta time  TDC1 total_time TIC1          ID
> A 1   0   1  48.50       1              1           1
> B 0   0   1  65.96       2               1           2
> B 1   1   2  65.08       2              1            2
> C 0   0   1  0.00        2               4           3
> C 1   1   2  0.00        2               4           3
> D 0   0   1 72.74        2               5           4
> D 1   1   2 72.52        2               5           4
> E 0   0   1 61.84         2              3            5
> E 0   1   2 60.56        2               3            5
> F 0   0   1 35.04        4               2            6
> F 0   1   2 36.97        4               2            6
> F 0   2   3 37.92        4               2            6
> F 1   3   4 39.01        4               2            6

Duplicated rownames are no allowed.

>
> time - time to event
> sta - starting time
> TDC - time dependent covariates
> TIC - time independent covariate
> total_time - total time at risk
> ID - ID
>
> 1- What happens if the ID is not included?
Read the documentation
> 2- How can I solve this error?
Read the documentation
> 3- Why the phreg function does not need an ID?
Read the documentation (and a good text book on survival analysis)

And please read the posting guide; the elementary information is missing.

>
> Thanks,
>
> Javier
>
>
> --
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> Sent from the R help mailing list archive at Nabble.com.
>
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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.
>



-- 
Göran Broström