I have a data for the urine test results. Two samples have been taken from each patient in different days and tested by the LAM test and urine dipstick for different biomarkers. The data looks like this:

Subject   SampNum LAMresult dipstick_bio1 dipstick_bio2 ...
 1           1       1           2            + 
 1           2       0           1            -
 2           1       1           3            . 
 2           2       1           2            +

I would like to find the impact of the dipstick biomarkers on the LAM test positivity using a logistic regression. I am using the following SAS code to carry the logistic model:

proc logistic data=data descending;
  class dipstick_bio1  dipstick_bio2 .../ param=ref ;
  model LAMresult = dipstick_bio1  dipstick_bio2  ;

Shall I include the test results separately for the samples collected on different days or all together?


1 Answer 1


You can use a mixed effects logistic regression model here, which will take account of the non-independence within subjects. Basically you need to fit random intercepts for subjects. I don't really know SAS but i believe you might need PROC GLIMMIX


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.