Dear Stata users,

I am struggling to understand "the Difference in eGFR change" in the following table and why the value does not simply equal or close to the difference of 'Adjusted eGFR change' between each category and the reference category. I am wondering how Stata calculates the difference between groups compared to the reference (linear mixed model) and why the value does not simply equal or close to the difference of 'Adjusted eGFR change' between each category and the reference category?

Thank you in advance.
Array