topic How to calculate person years in Cox regression? in SAS Programming

How to calculate person years in Cox regression?

nwang5 — Wed, 29 Mar 2023 18:58:02 GMT

Hi all,

I hope you are doing well. I am trying to calculate person years. I am not sure if there is any code we can use in proc phreg to get person year and number of events directly.

I also have another question. I selected participants who did not have health outcome and try to calculate person year by hand. I was wondering if there is any code I can use to get the sum of each product of each column* time: h:persist good person time=2*176+4*340+6*272+.......

176

238

340

476

272

393

319

409

229

307

247

319

1275

143

1560

Total

2858

221

245

378

3702

Thanks!

Re: How to calculate person years in Cox regression?

ballardw — Wed, 29 Mar 2023 20:13:32 GMT

Please provide example data in the form of data step code. Instructions here: https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-data-AKA-generate/ta-p/258712 will show how to turn an existing SAS data set into data step code that can be pasted into a forum code box using the </> icon or attached as text to show exactly what you have and that we can test code against.

If you can't manage that at least post the example as simple text in a text box. That particular tabular layout is not worth trying to write a data step with.

My first thought would be Proc Means/ summary with your Time variable as a Weight variable and then request a Sum for the other variables. DO not include the Total row, if you have such in your actual data set, as it is obviously not a numeric variable and a Weight variable must be numeric.