Hi Everyone,
I would appreciate if you could please help me with the following question.
What I have:
I have three variables, Year_of_visit, employment status (UNEMP), and HIV_ status. I also have 5 participants. Participants were asked about their employment status in different years. When the UNEMP is 0 it means the person is employed and when it is 1 it means the person is not employed. In each year of visit, they were also tested for HIV status. If HIV test is 0 then the person is not infected if HIV_status is 1 then they are infected.
What I want:
I am conducting a survival analysis (using PROC PHREG) on the association between the Unemployment (UNEMP) and HIV outcome. However, the employment status of participants changes in different years. For instance, Case ID 1 is employed in years 2000 and 2001, then she was unemployed in years 2002 and 2003, and finally, she became employed again in 2004. Hence, the Unemp variable is time-dependent and changes over time. I want to make a third time-dependent variable based on UNEMP variable, which takes into account the time dependency of Unemp. Then I am going to use that variable in Proc Phreg analysis.
Thank you indeed for your help. Below is a code for what I have.
Data what_I_Have;
input CASE_ID Year_of_visit UNEMP HIV_Status ;
Datalines;
1 2000 0 0
1 2001 0 0
1 2002 1 0
1 2003 1 1
1 2004 0 1
2 2000 0 0
2 2001 0 1
2 2002 1 1
2 2003 1 1
2 2004 1 1
2 2005 1 1
3 2000 1 0
3 2001 1 0
4 2000 1 0
4 2001 0 0
5 2000 1 0
5 2001 1 0
5 2002 0 1
5 2003 1 1
;
Sorry, but i don't understand what "time-dependent" means. Please explain what the variable should contain.
SAS Innovate 2025 is scheduled for May 6-9 in Orlando, FL. Sign up to be first to learn about the agenda and registration!
Need to connect to databases in SAS Viya? SAS’ David Ghan shows you two methods – via SAS/ACCESS LIBNAME and SAS Data Connector SASLIBS – in this video.
Find more tutorials on the SAS Users YouTube channel.