Include Reference in PHREG for comparison

[ifti_ch2002]

I need to include reference category in Phreg in the table of 'Parameterestimates' for comparison between two levels, for example if i have sex as class variable, and female as ref, then in the table of 'Parameterestimates' only shows the hazard ratio of Male. What i need is to include the female as reference for sex and hazard ratio for that will be 1.

[FreelanceReinh · Accepted solution]

Hello @ifti_ch2002,

I think you should specify the param=glm option of the CLASS statement. This will include the reference level in the Parameterestimates ODS output dataset with HazardRatio=., which you can set to 1 in a subsequent data step.

Example (using the sample data from Example 89.3 Modeling with Categorical Predictors):

ods output parameterestimates=est;
proc phreg data=VALung;
class Prior(ref='no') Cell(ref='large') Therapy(ref='standard') / param=glm;
model Time*Status(0) = Kps Duration Age Cell Prior Therapy;
run;

data want;
set est;
if df=0 then hazardratio=1;
run;

[ifti_ch2002]

Oh Nice. Thanks