Displaying 8 results from an estimated 8 matches for "nearma".
2009 May 22
1
Forcing a variableinto a model using stepAIC
...isation period). I know that SAS can be used to do this but my
SAS coding is poor and consequently it would be easier for me to use
R, especially given the fractional polynomial transformations!
Currently the model is as follows (without treatment).
coxfita=coxph(Surv(rem.Remtime,rem.Rcens)~sind(nearma)+fsh(nearma)+fdr(nearma)+th1(nearma)+th2(nearma)+fp(cage)+fp(fint)+fp(tsb)+strata(rpa),data=nearma)
Thank you for your help,
Laura
2009 Jun 09
2
Isolating a single plot from plots produced simultaneously
Dear R-Help,
I am using the 'mfp' package. It produces three plots (as I am using
the Cox model) simultaneously which can be viewed together using the
following code:
fit <- mfp(Surv(rem.Remtime,rem.Rcens)~fp(age)+strata(rpa),family=cox,data=nearma,select=0.05,verbose=TRUE)
par(mfrow=c(2,2))
plot(fit)
They can be viewed separately but the return key must be pressed after
each graph appears (Click or hit ENTER for next page).
I'd like to isolate the second plot produced (the estimated functional
form of the influence of age on the log re...
2008 Sep 29
1
Hazard plot
Hi All,
This sounds a relatively simple query, and I hope it is!
I am looking at a continuous variable, age. I am looking at time to
12-month remission and can calculate the HR and 95% confidence interval are
follows:
coxfita = coxph(Surv(rem.Remtime,rem.Rcens)~nearma$all.age,data=nearma)
exp(coxfita$coefficients)
exp(confint(coxfita))
However, because I am looking at age as a continuous variable I cannot draw
a Kaplan-Meier curve. Instead I need to draw a plot of hazard against age.
How do I do this? I don't think
plot(nearma$all.age,coxfita$linear.predi...
2008 Sep 30
0
Hazard curves
-- begin included message -----
I am looking at a continuous variable, age. I am looking at time to
12-month remission and can calculate the HR and 95% confidence interval are
follows:
coxfita = coxph(Surv(rem.Remtime,rem.Rcens)~nearma$all.age,data=nearma)
exp(coxfita$coefficients)
exp(confint(coxfita))
However, because I am looking at age as a continuous variable I cannot draw
a Kaplan-Meier curve. Instead I need to draw a plot of hazard against age.
How do I do this? I don't think
plot(nearma$all.age,coxfita$linear.predi...
2009 Apr 03
2
Schoenfeld Residuals
Dear All,
Sorry to bother you again.
I have a model:
coxfita=coxph(Surv(rem.Remtime/365,rem.Rcens)~all.sex,data=nearma)
and I'm trying to do a plot of Schoenfeld residuals using the code:
plot(cox.zph(coxfita))
abline(h=0,lty=3)
The error message I get is:
Error in plot.window(...) : need finite 'ylim' values
In addition: Warning messages:
1: In sqrt(x$var[i, i] * seval) : NaNs produced
2: In min(x) :...
2009 Jun 23
0
Fractional Polynomials in Competing Risks setting
...the underlying model. However, I am now at the
situation where the assumption that the competing risks are
independent is no longer true and therefore I cannot use the Cox
model.
The code I used to get the MFP model was:
coxfitf <- mfp(Surv(with.Withtime,with.Wcens)~fp(all.age),family=cox,data=nearma,select=0.05,verbose=TRUE)
where with.Withtime is the time to treatment withdrawal, with.Wcens is
the censoring indictor for the event and all.firstint is the age at
baseline.
To look at the competing risks regression modelling when age in
untransformed, I can use the following code:
fitn<-crr(n...
2009 Oct 05
0
Unusual error while using coxph
...weeks without any
bother for various covariates. I'm now looking at another covaraite and
whenever I run the code you can see below I get an error message: "Error in
rep(0, nrow(data)) : invalid 'times' argument"
This code works:
# remove 'missing' cases from data #
snearma <- function(data)
{
for(i in 1:nrow(data)){
if(is.na(data$all.sp)[i])
data$all.sp[i]<-0
if(is.na(data$all.cp)[i])
data$all.cp[i]<-0
if(is.na(data$all.scgtc)[i])
data$all.scgtc[i]<-0
if(is.na(data$all.tc)[i])
data$all.tc[i] <- 0
if(is.na(dat...
2008 Oct 15
0
R-help Digest, Vol 67, Issue 31
....com>
Content-Type: text/plain
Hi All,
This sounds a relatively simple query, and I hope it is!
I am looking at a continuous variable, age. I am looking at time to
12-month remission and can calculate the HR and 95% confidence interval are
follows:
coxfita = coxph(Surv(rem.Remtime,rem.Rcens)~nearma$all.age,data=nearma)
exp(coxfita$coefficients)
exp(confint(coxfita))
However, because I am looking at age as a continuous variable I cannot draw
a Kaplan-Meier curve. Instead I need to draw a plot of hazard against age.
How do I do this? I don't think
plot(nearma$all.age,coxfita$linear.predi...