HI! I have performed a logistic regression with dichotomous dependent variable, 2 continuous independent variable, 14 dichotomous variables and 1 multi-level variable. All independent variables were significant in univariate logistic regression, except one. I have a problem with a specific variable (in theunivariate and so in the multivariate logistic regression), I obtain this result ODDS: Estimate >999.99 and the 95% Confidence Limits >999.999 - > 999.999. however, If I calculate OR by using proc freq using the dependent variable * independent variable, I have the following result estimate point: 1212.8991 and 95% Confidence Limits 1031.0208 1426.8618. It’s a huge problem because it is an important variable for excluding it, and I know that the problem is the unbalanced data (in one cell I have 147 observations out of 164.000). What can I do? I have tried also with Firth penalization without success, and to use exact analysis in proc logistic without success. I was considering also the proc glimmix but maybe I have not found the correct options to include… What can I do for using that variable in my model? Which approach can I try?? Please help me, thank you
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