I can't say for certain because I haven't fully explored the logistics, but here's a point for consideration. In my city, they have 3 different hospitals (not associated with each other). In addition to that, there are about 10 standalone ERs, all of which are associated with one of the hospitals. They could build one giant ED within the hospitals, but they chose to distribute them.
Another consideration for them compared to us, they have transporters. So, if they needed something or someone in a particular place, they could arrange that. I don't know if that's more an argument for or against centralized medical care.
I don't know the number of people, but it's not a huge city. My point wasn't how many my city has, it was the distributed part that might be helpful. I'm not saying they need 10+ different places like my city, but 2-4 places might work out better for them--I don't know.
My city also is not ready for battle with the Borg or prepared to take on alien pathogens. Their needs are clearly different.