Many political leaders have called on governments to evaluate the relative impact of various drugs and medical treatments in an effort to control health costs. But history has shown just how dangerous this approach to medicine can be, wrote Center for Medicine in the Public Interest's Robert Goldberg in The Oklahoman earlier this month.

Based on state-run comparative-effectiveness trials, Britain's National Health Service has been pushing patients onto a less expensive cholesterol-lowering drug called simvastatin in favor of Lipitor. While the British government has probably saved some money, it comes at a cost, according to Goldberg.

An eight-year study found that "major cardiovascular events" had increased by more than a third among patients forced to make the switch. As politicians grope for ways to control health care spending, they should be sure that their policies don't do more harm than good.

Comparative-effectiveness research has a role to play in fostering more cost-effective use of health resources -- but not at the expense of patient care.