Wednesday, January 16, 2013

Evidence Based Medicine

I was talking to a physician about “bio-identical” hormone replacement.  The doctor asked if there were any double blind, placebo controlled, randomized studies that demonstrate the safety and effectiveness of this type of therapy.  I replied no, but may I ask you a question?  Would you require this information to prescribe medication?  After an affirmative reply, I said, “so you have such a study that will back up everything you do and everything you prescribe in your practice”?  The physician pondered the question and replied, “You know that I don’t.”  We agreed that medicine should still be an art that applies knowledge and common sense to the individual being treated. 

As a sidelight, hormone replacement is perhaps the most well studied drug therapy ever!  And it is still the most misunderstood drug therapy on the market.

The gold standard for a study is a double blind, placebo controlled, randomized system.  This means you “randomly” select a group of people, you give half the real drug, and half a placebo but neither the individual nor the practitioner knows who is getting what.  Then the results are measured.  So let us say that we have a drug we expect to be good for lowering blood sugar.  We then monitor labs to hopefully verify the effectiveness of the drug.  We also monitor the other effects called “side effects”.  This includes the adverse effects to establish the safety of the drug.  If the placebo effect is 30 percent and those taking the drug have 33 percent effectiveness then we could say the drug is effective.  There have been drugs marketed with such low margins.  Such studies satisfy the legal criteria for approval and the justification for prescribing.  Most of these studies may last only a few weeks. 

These types of studies are about the herd effect.  If the drug happens to work for you then great, if it does not then you try something else.  This approach is not about the individual.  It is also not really health care, and it is not really scientific. Why?  For one science observes without a preconceived outcome.  Also, you can design a study with patient selection criteria that will offer the most positive results.  Do you really think a drug company will commission a study and spend the money without the high possibility of a positive outcome?   The term “Evidence Based Medicine” is wielded like a club that says “we are so much smarter now”. 

The physicist knows that just the action of observing can change the outcome.  This has been demonstrated in the laboratory.  In more common terms, does a child behave differently when his parents observe him at a ball game versus when they do not come at all?  The very act of observing can change the outcome.  Fascinating!

NIH Observational Cohort Study

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