A primer on the evaluation of therapeutics

I ' m actually going to talk here mostly about how we decide that medications are effective, but the basic principles apply to other kinds of interventions such as surgery, physical therapy, or devices. However, those do present some additional difficulties, which I won ' t go into right now. Conventionally, we speak of a hierarchy of evidence, from least to most persuasive. The weakest form of evidence is anecdote. Dr. Fell says he gave eye of newt to several of his patients with crotch rot and they got better. (This is essentially what started the hydroxychloroquine madness.)  There are many reasons why doctors all over the world don ' t rush out and start giving eye of newt to all their patients. Dr. Fell may simply be a nut. But even if he ' s sincere, with most diseases, presumably including crotch rot, and including Covid-19, most people normally get better. So Dr. Fell ' s observation doesn ' t show that eye of newt actually helped. He may be unconsciously motivated to see more or faster improvement than expected, because he wants his treatment to be useful. And there may be adverse effects that he overlooked or haven ' t emerged yet. He may also have, perhaps unconsciously, given the nostrum to patients who would be most expected to improve. There are more reasons to doubt this but I ' ll stop there.The next level of evidence is still considered too weak to draw any conclusions about the safety and effectiveness of a medication. This is called a retrosp...
Source: Stayin' Alive - Category: American Health Source Type: blogs