[R] AFT model time-dependent with weibull distribution

[javier palacios]

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
 
>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

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? 
2- How can I solve this error?
3- Why the phreg function does not need an ID?


Thanks,

Javier


--
View this message in context: http://r.789695.n4.nabble.com/AFT-model-time-dependent-with-weibull-distribution-tp3755079p3755079.html
Sent from the R help mailing list archive at Nabble.com.