I hadn't read it myself, but I remember that there are a lot of stories like these in Ian Ayers's Supercrunchers and the success of simple algorithms over expert judgment and the resistance thereto. And Superfreakonomics mentioned the story of how hard it was to get doctors to wash their hands as often as necessary.
A feature in Scientific American magazine casts some light on the troubled state of modern medicine.
Health Care Myth Busters: Is There a High Degree of Scientific Certainty in Modern Medicine?
Short excerpt:
Scientific American often gates its online articles after some time has passed, so I don't know how long it will be available.