Consider the impact of the following:
The Aging population in the US.
The ability to provide for Premature babies.
The effect of the expansion of third party payers (folks who pay the bill are not the ones shopping for medical services).
The effect of pressure on drug companies to develope new drugs
The effect of offering "free" medical care to the poor (Medicaid)
The effect of junk food diets. Here, I noticed that Mississippi and Alabama are the leading states for obesity (fried foods are king in the South).
The effect of treating cancer...years ago, few were treated,or the treatment was nominal. Chemotherapy was not well developed.
Since this is not my area of expertise, I searched Google under the key words "'health care costs' causes" to get these possible sources:
There are other sources available. In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.
I hope this helps. Thanks for asking.