I have to do a survival curve comparing 3 diseases. Already did a Kaplan Meier since time of diagnosis, and the log rank was p-0.001; however I suspect that it has to do with age (one disease is typical of old people). How can I adjust my curves to age? Thank you very much
One way to do this is to use the COXREG procedure with your grouping factor as a stratification variable and age as a covariate. Analyze>Survival>Cox Regression. Specify your time and status variables, the status value indicating the event, specify your grouping variable in the Strata box and age in the Covariates box. Click on Plots. Under Plot Type select Survival. Click Continue and OK.
If you want to fix age at a value other than the dataset mean, you can do that in the Plots dialog instead of leaving the default choice of mean.