commercial and residential construction applications. So I'm not aware of any issue with concrete in the column itself. Concrete filled support columns do often rust out, but that's due to their touching the ground and not to their being filled with concrete.

Make sure you tamp it down and there are no air pockets, use concrete with no chlorides in it, and treat the bottom part of the pole with rust resistant paint, and You shouldn't have an issue. That's what I'd do anyway.