I'm using phreg for the first time, and don't quite understand how it works. I'm fairly familiar with other procs (glm, etc), but phreg seems finicky. Here's my code: data survival;
input ID virus sex surv_days;
label virus='0=Ctrl, 1=Virus' sex='0=M,1=F' surv_days='survival';
datalines;
4264 1 1 3
4265 1 0 15
4269 0 0 15
4270 1 0 15
4272 0 1 15
4283 1 0 15
4284 0 1 15
4286 1 1 10
4288 0 1 5
4290 0 0 15
4293 1 1 7
4294 0 1 4
4296 1 1 4
4297 0 1 15
4299 1 0 8
4303 1 1 7
4304 0 1 15
4308 1 1 5
4310 0 0 15
4314 1 0 15
4316 0 0 15
4320 0 1 15
4325 0 0 15
4329 0 1 15
;
run;
data regimes;
Virus=0;
output;
Virus=1;
output;
Sex=0;
output;
Sex=1;
output;
run;
proc phreg data=survival plot(overlay)=survival;
model surv_days=sex|virus;
baseline covariates=regimes out=_null_;
ods output ParameterEstimates=surv;
run; From this, I have some questions: 1) my plot is only displaying 2 survival functions, labeled covariates 3 and 4. What happened to covariates 1 and 2? 2) why are my hazard ratios not displayed? 3) for my interaction (sex x virus), how do I determine which comparisons are significantly different? In proc glm, etc, I have used lsmeans / diff. That doesn't seem to work here. I feel like I'm doing something fundamentally wrong here. So any advice is greatly appreciated. Thanks.
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