Hi,
I am trying to obtain ROC curves using PHREG. SAS user's guide provide following code for SAS 9.4 with SAS/STAT 14.2:
ods graphics on;
proc phreg data=Liver concordance plots(overlay=individual)=roc rocoptions(at=2 6);
model Time*Status(0)=Bilirubin Age Edema;
run;
However, to address left truncation of the data I am using "ENTRY=' option and I am also performing stratified analysis since I have data from multiple studies. I am using following codes-
proc phreg data=dataset plots(overlay=individual)=roc rocoptions(at=5 10 15 20);
strata study;
model time*event(0) = x_num y_num / rl entry=entry_age;
run;
Apparently, the "entry" option and "strata" statement does not support ROC analysis. I am getting following messages in the log windows-
"Neither concordance nor ROC analysis is performed with the START/STOP specification of time."
"Neither concordance nor ROC analysis is performed when the STRATA statement is specified."
Can anyone please suggest a way to get around "entry" option and "strata" statement in order to get ROC curves?
Thanks in advance!
