Cox PH model ：Hazard Ratios is the blank problem

[zihmin]

Hello, I used the Cox PH model, but the output in the two rows with smokey=2 and stage=4 is blank, so I would like to ask how to solve the blank problem. (the logs do not show any warning)

Thank you !

proc phreg data=b;
class 
ID_S (param=ref ref='1') agep(param=ref ref='1') 
town1(param=ref ref='1')  ses (param=ref ref='1') 
smokeg (param=ref ref='0') smokey (param=ref ref='0') 
drinkg  (param=ref ref='0') cci_g (param=ref ref='0') stage (param=ref ref='0') 
histgp (param=ref ref='1') h_acc (param=ref ref='0') ;
model dd*readmit1(0)=h_acc ID_S agep town1 ses smokeg smokey drinkg cci_g stage histgp/risklimits 
slentry=0.25 slstay=0.15 details;
baseline survival=s /diradj  group=h_acc;
run;

[sbxkoenk · Accepted solution]

See :

DF=0 in PROC PHREG output (SOLVED)
https://communities.sas.com/t5/Statistical-Procedures/DF-0-in-PROC-PHREG-output/td-p/367227

PHREG doc : https://support.sas.com/documentation/onlinedoc/stat/151/phreg.pdf

Koen

[zihmin]

Thank you for your kind assistance.