I am currently trying to show if a certain medical marker, say X, predicts a poor outcome, say time spent in hospital. Both values are continuous. I performed a simple linear regression to determine r2, df, F, and the sig.
I want to test whether other markers are better at predicting the time spent in hospital than our marker. I was thinking of doing a multiple regression analysis, but the markers are related -> hence my multicollinearity rule would be broken.
Can I perform a simple linear regression for each marker and time in hospital and then compare the r2, df, F, and sig. to determine which marker better predicts time in hospital? Would this be breaking any statistical rules?