May 12 2010
Two recent acupuncture studies have received some media attention, both purporting to show positive effects. Both studies are also not clinical efficacy trials, so cannot be used to support any claims for efficacy for acupuncture – although that is how they are often being presented in the media.
These and other studies show the dire need for more trained science journalists, or science blogging – they only make sense when put into a proper context. No media coverage I read bothered to do this.
The first study comes out of South Korea and involves using acupuncture in a rat model of spinal cord injury. The researchers used a standard method of inducing spinal cord injury in rats, and compared various acupuncture locations to no-acupuncture control. They followed a series of metabolic outcomes, as well as the extent of spinal cord injury and functional recovery. They conclude:
Thus, our results suggest that the neuroprotection by acupuncture may be partly mediated via inhibition of inflammation and microglial activation after SCI and acupuncture can be used as a potential therapeutic tool for treating acute spinal injury in human.
The notion that acupuncture will actually improve outcome after acute spinal cord injury is, of course, extraordinary. This goes far beyond a subjective decrease in pain or some other symptomatic benefit. Therefore similarly extraordinary evidence should be required to support such a claim – and this study does not provide that.
In reading through the details of the study several factors caught my attention. The first is that there is no indication that the researchers were blinded. This alone calls the results into serious question. It is all too easy for researchers to allow personal bias to affect study results, even when they seem quantitative. We need look no further than the homeopathy research of Jacques Benveniste to see this (initial impressive results were investigated by Nature and found to be the result, charitably, if inadequate blinding).
Further, the researchers looked at several acupuncture points and then chose the ones that seemed to have an effect. This allowed for retrospective cherry picking – it is possible, in other words, that they received a scattering of random effects and chose the ones that appeared positive.
The effect sizes themselves, while statistically significant, were not clinically impressive. If they were real they would be useful in the treatment of spinal cord injury, but that is the point. Such small effect sizes are easily the product of randomness or bias.
And finally it should be noted that the study is coming out of South Korea. It is well established that countries where acupuncture is culturally important tend to have a much higher positive outcome rate than the same research in Western countries. The motivation to prove acupuncture seems to be a significant bias. Similarly, we recognize that there is a bias in favor of efficacy for pharmaceutical company sponsored research – the principle is the same. The bias of the researchers, even when well-controlled on paper, is measurable.
The bottom line with this study is that it provides weak evidence for a very extraordinary claim. It is of no practical use unless and until it is independently replicated with proper blinding. If you believe what you read in the media, however, you would be led to the conclusion that spinal injured patients could be made to walk again simply by sticking needles into magical locations on their body.
The second study uses quantitative sensory testing (QST) to look at pain threshold at baseline and after acupuncture and “electroacupuncture”. They conclude:
There were congruent changes on QST after 3 common acupuncture stimulation methods, with possible unilateral as well as bilateral effects.
In other words – acupuncture decreases the perception of pain. This small study suffers from the same primary problem as the other – it is described as only single-blinded. The subjects themselves were not blinded to whether or not they were getting “real” acupuncture vs a sham or placebo. The totality of prior acupuncture research has clearly demonstrated that such unblinded studies are all but useless. There is a significant placebo effect from getting poked with needles, and this is sufficient to explain the results of this study.
While QST is quantitative, it is still subjective. In fact, using QST has fallen a bit out of favor in neurological studies because the elaborate procedure is no more reliable as an outcome measure than straightforward sensory testing. QST is still reliant on the subjective report of the subject.
Further, this study mixed acupuncture with “electroacupuncture.” I strongly maintain that there is no such thing as “electroacupunture” – it is, rather, the application of transcutaneous electrical stimulation through an acupuncture needle. This is no more acupuncture than the application of morphine through a hollow acupuncture needle should be considered acupuncture.
It is possible that needling and electrical stimulation do decrease subjective pain perception (although we can’t conclude that based upon this study). One pain or sensory stimulation can certainly distract you from another. There is also the principle of counter-irritation – the inhibition of pain pathways by activating parallel sensory pathways. Bang your elbow and you will rub it to decrease the sharp pain.
Given the state of the acupuncture literature, such small and insufficiently blinded studies are of little value. It has already been established that there is a significant placebo effect surrounding the ritual of acupuncture and there are mechanisms of non-specific effects, such as counter-irritation. None of this can be logically used to support the underlying assumptions of acupuncture – that there is anything special about the designated acupuncture points, or that they can be used to manipulate “chi” or some other mysterious energy.
We are already well past the stage of preliminary studies in acupuncture. Only rigorously controlled studies are of any use. And the term “electroacupuncture” causes only confusion and cannot be meaningfully used. It is the blurring of variables when good science should endeavor to isolate variables.
Also, in a perfect world, the general press would not report on every preliminary study as if they were a definitive medical breakthrough. Such medical news stories should be covered in more focused outlets that have the space and expertise to put the results into a reasonable context.
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