Most of it is medication related.
Opening up a whole 'nother can of worms. A great way to cut costs in healthcare would be for doctors to follow protocols for prescribing medications, to do some testing and retesting to determine need for, efficacy of, and continuing need for medications. Maybe not to automatically go for the latest and greatest (and practically the same as last year's latest and greatest) drug out there that the rep convinced them was just the niftiest thing since sliced bread.
I like my doctor a whole lot. But what she doesn't know about the five hundred bucks' worth of medication she has me taking every month could, and does, fill a couple textbooks. Maybe doctors should work more closely with pharmacists. Maybe the patent expiration system needs changing so that companies aren't constantly looking for ways to reinvent the wheel in order to stay profitable.
I'm not sure how, but I know that huge part of the problem is expensive drugs and the way they are prescribed: generally with very little regard for side effects and interaction, often several kinds of drugs that may or may not work be necessary or work well together.