I have a question that I hope you can help me with. I often use the Cox’s hazard regression with the PHREG procedure of SAS fitting multivariable models with several covariates. Below is an example of a model I used to analyze time to pregnancy in cows according to several covariates (all categorical covariates) DPREG= Days to pregnancy PEND = Pregnant at the end of study (0 or 1) Covariates in the model are 4, all categories, and each with 2 levels: PTACCR, EXPN, PARPRE, and AIGRP I obtain covariate adjusted survival functions with the BASELINE COVARIATES function in SAS. My question to you is how can I obtain the covariate-adjusted median survival times and the respective 95% CI for each level of each covariate in the statistical model? I request the predicted days when 50% of the population survives (OUT=PRED), but it does not give me the 95% CI. If I use PROC LIFETEST, I obtain the median days to event and respective 95% CI, but those are from univariable models without multiple covariate adjustments; however, I would like to obtain the median days to event and respective 95% CI from the multivariable model in PHREG. Is there a function or code in SAS PHREG that allows me to obtain the median days to event and respective 95% CI from the multivariable model (median days adjusted for covariates)? ODS HTML; ODS GRAPHICS On; PROC PHREG DATA=GENONEW PLOTS (OVERLAY)=SURVIVAL; CLASS PTACCR EXPN PARPRE AIGRPN; MODEL DPREG*PEND(0) = PTACCR EXPN PARPRE AIGRP/ RISKLIMITS TIES=EFRON; BASELINE COVARIATES=GENONEW OUTDIFF=DIFFSURV OUT=PRED SURVIVAL=_ALL_/DIRADJ GROUP=PTACCR; OUTPUT OUT=OUTPUTFILE XBETA=Xb STDXBETA=SE RESMART=Mart RESDEV=Dev; HAZARDRATIO PTACCR; ASSESS PH/RESAMPLE; RUN;
... View more