Dear colleagues. I already have definided the failure event (DEAD) and time variable (TIME), and I have three groups with different treatment (groups 0, 1 and 2; variable GROUP). I calculated the incidence rate in each treatment group using the command "stptime, by(grupo)" and also I have the CI for each rate. I want to compare with a test (and I want to get a p value) the three incidence rates but just can compare 0 vs 1, 1 vs 2 and 1 vs 3 using comand "stir grupo if grupo==0 | grupo==1" and "stir grupo if grupo==1 | grupo==2" and "stir grupo if grupo==0 | grupo==2". Using "stir", I get a p value but just for two groups.

Do you know which command I should use to compare the IR among the three groups?? I know I would not get a incidence rate ratio between 3 groups but I need to compare all the three IR instead 0 vs 1, or 1 vs 2 or 0 vs 2.

Thank you so much, Alejandro Di Sibio