I have a group of 196 patients. I want to know if infection (the outcome, or dependent variable) depends on other variables. I am running a binary logistic regression with 8 independent variables (age, gender, type of surgery—6 different types, type of fixation, type of antibiotics). The categorical variables are automatically put into dummies by SPSS.
Some of my categorical variables have low frequencies (<5).
Can I run a binary logistic regression? Are the results reliable?
Update:
I have no categories with 0 patients, only some with only 1 or 2 patients. So I ran the regression and SPSS gives me the output above. Can I say that TRTCD2
and QSORRES
are statistically significant? And that the p value or 1 or almost 1 are due to the small frequencies in this group?