I'm not even going to mention why it took fifteen hours to get from DC to Boston. By plane. Except that US Airways sucks. Anyway, you might have heard about the placebo-effect article recently published in PLoS One. I was going to blog about this yesterday, but events overtook my schedule (by twelve fucking hours). Anyway, when I was visiting relatives, I decided to actually read the article, and I had some serious doubts about the conclusions.
Fortunately, I don't have to discuss them, since I found two good posts dealing with this article.
PalMD makes the good point that paying attention to patients is actually treatment, so the placebo effect, whether known or not, isn't surprising.
David Gorski deals with a bunch of issues, but the one I'm especially glad he broached is the issue of the scale that they use:
I find it rather interesting that the way the authors chose to frame their results in the actual manuscript, compared to how they described their results to the media. One wonders whether saying that 60% of subjects taking placebos felt better compared to 35% receiving regular care feeling better sounded more convincing that citing improvement scores like the ones listed above. The reason is that I very much wonder whether the improvements reported are clinically significant. For instance, in the main result reported, those in the notreatment arm reported an average IBS-GIS of 4 (no change). In the Open Placebo arm, the average reported was 5 (Slightly Improved). How clinically relevant is this? I don't know, but it sure seems to skirt the borders of clinical relevance and might not even achieve it. Come to think of it, the reason why news stories reported the results the way they did becomes clearer.
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Not long ago, I predicted (in a blog post) that a medically valid effect (meaning one that is measurable and not just the effect PalMD is talking about) would be found with orally ingested placebos given for GI related disorders or diseases. Not all the time, just some time. This is because the placebo that consists of ingesting via the mouth and throat, into the stomach and beyond, a bunch of sugar pills with water is not a proper control for a condition that involves any of those organs. And then, along comes this paper, which I also plan to blog about but, alas, have not read yet.
I agree with PalMD on 'attention' being a treatment. It's a darn good one too!
I also agree with Greg. 'Placebo' in the case of these GI disorders shouldn't be something taken orally with water and sent right into the organ system in question.