What is the biggest challenges facing the health care delivery system today?

System Broke(n): Let's see...We spend more than any other country in the world per capita on healthcare (18% of gdp, twice that of japan), 50% of which is spent on only 5% of the population, our life expectancy is ~30th in the world, 40% of our population is un(der)insured, and the who lists us as the 37th best country for care, just behind costa rica! why? Only 5% of our healthcare $$ are spent on prevention.