[Schneed10]

Also, it should be noted that the geography of the United States lends itself to an expensive healthcare system. We're spread out across a lot of square miles.

Conversely, Europe and Japan are tightly packed. When tightly packed, you gain economies of scale by having fewer access points to care. It makes for fewer locations to staff up. However when spread out geographically like the US, you can't just have a number of hospitals in Chicago and then a number of hospitals in St. Louis, you need a number of centers in between to accomodate emergency care.

While building costs wouldn't vary between countries (you'd simply scale the size of the building to the population density in the area), you still have to staff each facility adequately to handle patient needs. The more facilities you have to staff, the more costly it gets.