It's not particularly surprising that a country several times larger than another pays more money for health care. Are you saying the per capita cost is higher?

Per capita medical costs in the US are double that of most Western countries. Both private and public.

http://www.pbs.org/newshour/rundown/health-costs-how-the-us-...

This would seem a good statistic to cite when trying to show the comparative inefficiency of the American system.