How to adjust variable for Survival Analysis in SAS

Question

Im running a survival analysis and I have a variable 'age' where the data ranges from 30-90 years old but how do I cut it off and make it so the survival probability graph will only include up to the age of 60? Also how might I group them in categories of say 30-50 years, 50-70 years, and 70-90 years?

This is my code so far:

proc lifetest data=lungcancer plots=survival(atrisk);
time survival*status(0);
strata age / test=logrank;
run;

Answer 1

So, a quick disclaimer - I haven't used PROC LIFETEST, and don't have access to a SAS environment right now. Regardless, I think this might point you in the right direction.

how do I cut it off and make it so the survival probability graph will only include up to the age of 60?

You could use the WHERE= Data Set Option: https://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a000131192.htm

Your PROC step would look something like this:

proc lifetest data=lungcancer(where=(age<=60)) plots=survival(atrisk);
time survival*status(0);
strata age / test=logrank;
run;

Also how might I group them in categories of say 30-50 years, 50-70 years, and 70-90 years?

The STRATA statement in PROC LIFETEST might resolve your issue: https://support.sas.com/documentation/cdl/en/statug/63033/HTML/default/viewer.htm#statug_lifetest_sect008.htm

Or, perhaps, the BY statement: https://support.sas.com/documentation/cdl/en/statug/63033/HTML/default/viewer.htm#statug_lifetest_sect005.htm

Hopefully this is some help.