Sunday, February 23, 2014

Do Doctors Practice Evidence Based Medicine?

I advocate evidence based medicine.  We should restrict our medical recommendations to those that have a reasonable underlying scientific basis.   On the opposite end of this spectrum is quackery, when snake oil and other potions are hawked that either have no scientific support or have been shown scientifically to be ineffective.

I do not offer snake oil here as a historical reference.  We have more snake oil and its congeners today than ever before.  People who are sick want to believe the man who promises them healing, particularly when conventional medicine has not succeeded.  This belief goes to the core of human nature, at least as I have observed over the past 3 decades. 

Of course, in the medical world, we don’t have enough science yet for all of the medical issues that we physicians confront.   That means that we guess a lot.  How often does this occur?  Every single day.   Patients would be quite surprised to learn that there is usually scant or conflicting medical evidence to guide the issue that has brought them to our offices.   This does not mean that your physician is rolling the dice on you.  He relies upon available medical knowledge, if there is any, and his judgment and experience, two invaluable assets that are not measured in the various pay-for-performance schemes.   These invaluable assets are not measured and rewarded by the government and insurance companies because they cannot be easily measured.  Does that mean that they don’t count?  Absurd, of course.

If you doubt the presence of non-evidence based medicine, consider the promised health benefits of yoga, probiotics, medication, massotherapy and the latest gluten free rage.  I’m not stating categorically that these and related techniques do not work; I am pointing out that there is no persuasive medical evidence supporting their claims.   Our airwaves are clogged up with snake oil disguised as medicines promising ‘good prostate health’ or ‘healthy bones’.  These sound like health claims to me, but their language is carefully selected and is followed by the disclaimer ‘not designed to diagnosis or treat any medical disease’.   Would you rather believe the false promise or the true disclaimer?

Of course, these prostate potions do not want to be subjected to rigorous scientific scrutiny.  Why would they?  They do not need FDA approval like prescription medicines.  They can freely and legally use the phrase ‘clinically tested’ (whatever that means) and empty their warehouse shelves to clogged prostates across the country.   These companies only have to spend funds on marketing, unlike true drugs that must spend millions demonstrating to the FDA that their products are safe and effective.

There are many products on the market today that don’t want to be tested to confirm or determine efficacy.   Guess why.


  1. I strongly disagree with your view of the literature. Of course many traditional practices that existed long before the recently invented RCT have not yet been tested - because the resources don't exist, not because the evil Quacks don't want to - and there is indeed a good leavening of sheer quackery. But several of the things you mention actually have been tested and found useful for various purposes, as have many others that are demonized as alternative. For example, there are now close to twenty human clinical trials showing that probiotics can slash the rate of antibiotic-caused diarrhea and C.diff infection, with pretty low NNTs. Based on published science, I will never again take an antibiotic without a probiotic supplement. If an MD proceeds to sneer and call me irrational for that, that will be the last time I am seen in his office. I don't object to your not reading all those studies or not even knowing about them - keeping up with all relevant literature is an impossible task - but don't treat me badly because I happen to have seen some literature you haven't.

  2. I thank the anonymous commenter for your thoughtful response. I admit readily that I have large pockets of medical ignorance and that you may know legitimate medical information that I am not aware of. I agree that you should have a high threshold for accepting antibiotics or drugs, in general. While I am certainly aware of the studies you mention, using probiotics to prevent C diff or antibiotic-associated diarrhea is not established treatment. This does not mean, as I indicate clearly in the post, that they have no role here, only that their use is ahead of supportive science. Indeed, I have used probiotics in similar cases, but have not presented them as having a proven use here. I think that we can both acknowledge that there is a rampant use of probiotics today, often without any scientific basis. Lots of faith out there in the medical arena. If we're prescribing or accepting treatment on faith only, we should at least admit this.

  3. Dr. Kirsch-

    Great post, and there's not doubt that much of medicine has little to no evidence behind it, but it's still a heckuva lot more than the medicine masqueraders out there.

    I'm trying to contact you about another subject but couldn't find an email on your blog. Would you mind emailing me at editor (at) whitecoatinvestor (dot) com?


  4. I'm the original commenter; thanks for your response. In my view there is supportive science to use probiotics to prevent harm from antibiotics; the question of how many trials is "enough" is a value judgement. When the supporting evidence is more limited, e.g., in their use for weight loss, I would still hesitate to term that use "faith." Lots of decisions must be made based on imperfect knowledge of possible benefits and costs. Deciding how much evidence, and of what kind(s), should be required before you try something to see if it works for you requires multiple value judgements. Almost anyone viewing others' value judgements will be inclined to term those he dislikes "faith" or "irrational", while those he likes are "rational" or "reasonable".

    At least, the use of an alternative or traditional remedy is no more faith-based than the use of an unproven, disproven, or nil-net-benefit conventional practice. For that matter, epistemologically, you could say most patients do what you say based on faith (or an argument from authority) rather than reason. If you tell them that they should take some long-term drug, most don't hit the library to try to estimate their own personal NNT and NNH; they just believe you. You might like the decision better, but it's not based on any keener exercise of intellect than the person who reads some animal studies of a dietary supplement and decides that it is safe and cheap enough to be worth trying.

  5. I think Dr. Ben Goldacre, in his book Bad Pharma draws the curtain back on just how little evidence-based medicine is available. From skewed trials to biased publishing . . . doctors, despite best efforts to stay abreast of current literature, are poorly served by academic/pharma based medicine. Finding a way through the labryrinth appears to be a Herculean task, which most doctors are not equipped to undertake. If you haven't read Dr. G's book, I'd highly recommend. At least you could understand some of the cynicism piled on the medical community--both conventional and 'quackery.'


  6. Ok heres a question, There is medical evidence and papers about topical steroid withdrawal...There is a Dr. who in the 70s did clinical studies on this. And a Dr. in Japan that also did studies. There are over 2000 people going through it right now with blogs and pictures and its all the same..So why if I take this information to our dermatologist, he acts offended and says there is no such thing?
    These are not quacks. They are real MDs that are still in practice. How many Dr.s does it take to make a condition real?