Displaying 4 results from an estimated 4 matches for "surv1".
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srv1
2009 Feb 18
1
Age as time-scale in a cox model-How to calculate x-time risk?
Dear R users,
My question is more methodology related rather than specific to R usage. Using time on study as time in a cox model, eg:
library(Design)
stanf.cph1=cph(Surv(time, status) ~ t5+id+age, data=stanford2, surv=T)
#In this case the 1000-day survival probability would be:
stanf.surv1=survest(stanf.cph1, times=1000)
#Age in this case is a covariate.
#I now want to compare the above estimate to the 1000-day survival probability I get using age at entry and exit as my time-scale:
stanf.cph2=cph(Surv(age,age+time, status) ~ t5+id, data=stanford2, surv=T)
stanf.surv2=survest(stan...
2009 Feb 19
0
Age as time-scale in a cox model
You asked about survival curves with age scale versus follow-up scale.
> fit1 <- coxph(Surv(time/365.25, status) ~ t5 + id + age, data=stanford2)
> surv1<- survfit(fit1)
> surv1
n events median 0.95LCL 0.95UCL
157.000 102.000 1.999 0.898 3.608
> summary(surv1, times=3)
time n.risk n.event survival std.err lower 95% CI upper 95% CI
3 46 85 0.451 0.0425 0.375 0.543
I've taken the lib...
2004 Nov 17
1
frailty and time-dependent covariate
...s a statistical problem due to the model formula or if it could be a problem related to my data.
Thanks a lot
Emanuela Rossi
> fit_19_1<-coxph(Surv(DATA_INI1,DATA_FIN1,EVENT1)~ V1+V2+alt1+alt2+strata(autocorr1)+cap1+SP+SP2+SP3+SP3:log(DATA_FIN1)+D1500+D3000+D4500+frailty.gaussian(ID),data=SURV1)
Warning messages:
1: Inner loop failed to coverge for iterations 1 3 in: coxpenal.fit(X, Y, strats, offset, init = init, control, weights = weights,
2: longer object length
is not a multiple of shorter object length in: offset + coxfit$fcoef[x[, fcol]]
3: X matrix deemed to be singula...
2009 Apr 23
0
Cox regression
...hat I was hoping I could get some advice on.
The first thing is that when I run an ordinary Cox regression in R I get the same results that I do using Stata (provided that I specify the Efron method for handling ties) but I also get the following warning message:
"Warning message:
In coxph(Surv1 ~ Out + site + haem) :
X matrix deemed to be singular; "
Is this warning important and definitely applicable? I would have thought that if there was a problem with the data I would also get some sort of warning in Stata?
The second problem concerns the estimation of a weighted Cox regre...