From an excellent NPR story on the puzzling regional variations in health care; there are adjacent towns with similar populations in which some medical procedures are performed five times as often in one as in the other. And more procedures does not lead to better care:
A couple of years ago Keller and some colleagues did an elegant study of one kind of back surgery in Maine, a procedure called discectomy. Keller found communities in Maine that had high rates of this surgery, communities with low rates, and communities that were somewhere in the middle. Then he followed patients who had had surgery in those communities over a five-year period to see how they fared. Keller says the conclusion was undeniable.
"In the high rate of surgery overall, the patient outcomes were the least good of those three categories. In the middle rates, the outcomes of the patients were in the middle. And in the low-rate areas — less frequent operations per capita — the outcomes were the best."
The reason that areas with more back surgery did worse, Keller says, is that doctors in those areas were operating on people whose issues were less severe; that is, patients who might not have been good candidates for an operation. So the problems associated with the surgery probably outweighed the problems of their actual sickness. For them, more wasn't better.