Here's a quick way for the U.S. government to save over half a billion dollars. Stop paying for coverage of medical procedures that have little or no evidence to support them.

The Centers for Medicare and Medicaid Services (CMS) now releases annual reports of how much it spends, broken down according to the procedures. Their latest data, for the year 2015, reveals that Medicare spent $564,165,721 on pseudoscientific medical practices.

I'm talking about chiropractic and osteopathic manipulation. These are similar but distinct belief systems, both involving bones, and both with no evidence to back them up. Most people think that chiropractors' spinal "adjustments" can relieve pain from injured or aching backs. It turns out that it's just an elaborate placebo: a back rub at home is likely to work just as well. And that home treatment is probably safer–I'll get to that below.

Osteopathic manipulative therapy (OMT) is another hocus-pocus belief, invented out of whole cloth in the mid-19th century by Andrew Still. He believed that every part of the body was linked by a mysterious "myofascial continuity" and that manipulating it could treat a vast range of aches, pains, and other ailments. Most of this is not true. (There is some evidence that OMT can be beneficial in carefully selected cases of lower back pain, but the CMS codes don't distinguish different uses of OMT.)