

Hi there,

Can anyone please help me because I am going to get crazy with the pbc data set. I just want to apply simple cox regression in the data set. I am a beginner in R but I don't think I am doing anything wrong. 

I have the book of Fleming and Harrington 1990. I perform cox regression by typing:

out<- coxph(Surv(times/365,status)~log(bili)+log(proth)+edema+log(albumin)+age)
out


Call:
coxph(formula = Surv(times/365, status) ~ log(bili) + log(proth) + 
    edema + log(albumin) + age)


                coef exp(coef) se(coef)     z       p
log(bili)     0.8636    2.3716  0.08294 10.41 0.0e+00
log(proth)    2.3868   10.8791  0.76851  3.11 1.9e-03
edema         0.8963    2.4505  0.27141  3.30 9.6e-04
log(albumin) -2.5069    0.0815  0.65292 -3.84 1.2e-04
age           0.0396    1.0404  0.00767  5.16 2.4e-07

Likelihood ratio test=231  on 5 df, p=0  n=416 (2 observations deleted due to missingness)

Which is not exactly what fleming presents in table 4.6.3 page 195. Edema coef is 0.8592.

I searched the net (please google: modern regression methods for survival data stockholm)

and there some slides there. The results of the slides are again slightly different and the analysis seems to be in R. So we all disagree. (I notice that 2 observation are excluded in my analysis, but not in the slides' analysis)

Also I check the age column, in the book the first two elemets are, 58.7652 and 56.4463 while in R 58.80548 56.48493. Age looks totally different.

Can anyone please help me. Also in the article "Survival model predictive accuracy and ROC curves" , which is free just google it, in page 27 the results seem to be different again. (caution with log(alb) or alb).

Does anyone has any information about this data set that clarifies things for me??


Leo.





      
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