In an excellent article in the BMJ, Nicholas A Christakis, professor of medical sociology at Harvard, asks the questions all doctors (and their patients) should be asking. He points out that too often these days we misunderstand (or maybe misuse) the results from drug trials.
Doctors say that a drug “works” if, in comparison with the control arm of a clinical trial, significantly more people in the treatment arm respond. Unfortunately, this is a naive oversimplification, and it breeds complacency among patients and physicians alike
He points out that it is frequently the case that a drug which is shown in trials to help more patients than a placebo or other treatment, very often actually only delivers this benefit for the minority of patients who are actually prescribed it. I’ve quoted Dr Roses of GlaxoSKF a few times on that same point!
Countless drugs that have been shown in randomised controlled trials to be effective work in only a minority of patients. Imagine that a drug worked 20% of the time in a trial, compared with 5-10% for a placebo. This is the case for drugs ranging from antihypertensives to minoxidil to cancer chemotherapy. Such a difference in a trial corresponds to an enormous effect size. However, most patients taking such drugs would not benefit—they would hardly think that the drugs “worked.” If you buy a toaster you expect it to be able to toast bread every time it is used. If it does not, you say it does not work and return or discard it. You do not take solace from the claim that, in fact, 30% of the time in the manufacturer’s laboratory the toaster did a better job in browning bread than sunshine alone.
It does amaze me that certain treatments are labelled “proven” in this way. What’s even worse though is when the prescribing doctor then seems to blame the patient for their “failure” to respond to the treatment. This leads me on to the author’s recommendation –
one appropriate reaction is to have a protocol of administration that evaluates a patient’s response. Doctors sometimes already do this in a systematic way (such as when titrating the administration of highly active antiretroviral treatment). But this practice should be more widespread and more formal
Whilst I agree with this recommendation, it still does amaze me. Don’t all doctors routinely check how every individual patient is doing?
Anyway, here’s the take home message, in the last paragraph of the article –
Just because drugs work in trials does not mean they will work in our patients. In fact, we can often expect that they will not work at all.
Heroes Not Zombies 
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