Why Do We Need Evidence Based Medicine?

Harriet Hall, who writes for Science-Based Medicine, discusses the importance of evidence based practice in medicine. Often the inherent psychological flaws of human reasoning lead individuals to assume that treatments are efficacious when really a successful outcome is independent from the treatment. The article is available here (Science Based Medicine, August 18,2009). A short excerpt below:

Sometimes We Get It Wrong

How can you know whether a medical treatment really works? If everybody says it works, and it worked for your Aunt Sally, and you try it and your symptoms go away, you can pretty well assume it really works. Right?

No, you can’t make that assumption, because sometimes we get it wrong. For many centuries doctors used leeches and lancets to relieve patients of their blood. They KNEW bloodletting worked. Everybody said it did. When you had a fever and the doctor bled you, you got better. Everyone knew of a friend or relative who had been at death’s door until bloodletting cured him. Doctors could recount thousands of successful cases.

All those people got it wrong. When George Washington got a bad throat infection, his doctors removed so much of his blood that his weakened body couldn’t recover, and he died. We finally got around to testing bloodletting and found out it did much more harm than good. Patients who got well had been getting well IN SPITE of bloodletting, not because of it. And some patients had died unnecessarily, like George Washington.