topic Re: Sample Size Calculation for Cox (Proportional Hazards) Regression in Statistical Procedures

Sample Size Calculation for Cox (Proportional Hazards) Regression

shakabra09 — Thu, 07 Dec 2017 21:45:00 GMT

I am having trouble understanding why the 'coxreg' option in proc power doesn't work for me. Everything I have read said to use that option to in order to determine the number of events needed, when I have an estimate for the HR and power that I want the study/analysis to have. Is it available anymore? If not, what other options are there in SAS to calculate this? I am using SAS 9.4 TRS Level 1M2. Windows Version 6.1.

proc power;
     coxreg;
run;

proc power;
     onesamplefreq;
run;

Obviously the code above is not complete, but in my program 'coxreg' from the first example is red (meaning it's not recognized, unlike the 'onesamplefreq' option below it).

Re: Sample Size Calculation for Cox (Proportional Hazards) Regression

Reeza — Thu, 07 Dec 2017 21:47:49 GMT

program 'coxreg' from the first example is red (meaning it's not recognized, unlike the 'onesamplefreq' option below it).

That's not necessarily true. The editors just not smart enough sometimes.

Re: Sample Size Calculation for Cox (Proportional Hazards) Regression

shakabra09 — Thu, 07 Dec 2017 22:02:27 GMT

From my log:

1 proc power;
NOTE: Writing HTML Body file: sashtml.htm
2 coxreg
------
180
ERROR 180-322: Statement is not valid or it is used out of proper order.

I should have included this in my original post...

Re: Sample Size Calculation for Cox (Proportional Hazards) Regression

Reeza — Thu, 07 Dec 2017 22:12:09 GMT

What version of SAS/STAT do you have?

proc product_status;run;

Or how about the demo code:

proc power;
   coxreg
      hazardratio = 1.4
      rsquare = 0.15
      stddev = 1.2
      ntotal = 80
      eventprob = 0.8
      power = .
   ;
run;

Re: Sample Size Calculation for Cox (Proportional Hazards) Regression

shakabra09 — Thu, 07 Dec 2017 22:19:49 GMT

What version of SAS/STAT do you have?

proc product_status;run;

13.2

Or how about the demo code:

proc power;
   coxreg
      hazardratio = 1.4
      rsquare = 0.15
      stddev = 1.2
      ntotal = 80
      eventprob = 0.8
      power = .
   ;
run;

10   proc power;
11      coxreg
        ------
        180
ERROR 180-322: Statement is not valid or it is used out of proper order.

12         hazardratio = 1.4
13         rsquare = 0.15
14         stddev = 1.2
15         ntotal = 80
16         eventprob = 0.8
17         power = .
18      ;
19   run;

Re: Sample Size Calculation for Cox (Proportional Hazards) Regression

shakabra09 — Thu, 07 Dec 2017 22:30:22 GMT

It looks like that is my problem, SAS/STAT 13.2 doesn't support coxreg. I need to make sure I use that User's Guide. Thank you!

Re: Sample Size Calculation for Cox (Proportional Hazards) Regression

Reeza — Thu, 07 Dec 2017 22:31:56 GMT

http://support.sas.com/documentation/cdl/en/statug/67523/HTML/default/viewer.htm#statug_power_toc.htm

Unfortunately SAS / STAT 13.2 doesn't have COXREG as an option.

If you have a valid maintenance license, upgrades are free.