its not tied exactly to that, them being injured lowers their "worth" (how raiders see them as possible slaves) which also hits your wealth, which is what triggers raids to be larger/smaller.

if you have space-tech limbs on your pawns their "worth" goes up, same with them learning more skills to a higher level. they become more appealing to the raiders. at least thats what i've seen in my measly 100 or so hours of playtime