Tuesday, May 12, 2009

Acupuncture - A Study with Toothpicks

I came across this article today reporting on a study comparing four types of lower back pain treatment over 7 weeks: individualized acupuncture, standardized acupuncture, "sham" acupuncture using toothpicks, and a control group that just used painkillers and anti-inflammatories (all groups were allowed to use drugs). Though I don't have the original journal article (May 11 Archives of Internal Medicine), the sample size seems large enough that the effect size mentioned should be statistically significant. 40% of the control group reported "significant improvement in disabilities brought on by back pain", and 60% of each of the other three groups reported the same. What might this mean for recommended treatments and third-party payment?

First, keep in mind that the participants all knew that this was a study on acupuncture treatment in order for the study to get informed consent. Only people willing to receive acupuncture were involved, which means the study had self-selection biases. Then they were randomly assigned to the four groups. So, the control group knew it was not getting the treatment that the study was testing. This would definitely have led to expectation biases in reporting disability. This study compared people willing to try acupuncture who got what they were told was acupuncture to people willing to try acupuncture who were then not given it. The chances that the effect seen is due to the placebo effect are very high.

The placebo effect is real and practically significant. It is really amazing how thoughts and beliefs, activity in the pre-frontal cortex, affect other parts of our brains and bodies, stimulating immune response (or inhibiting it) among other phenomena. What is also nifty is that we can intentionally generate these effects in ourselves without being tricked. Once we understand that a placebo effect exists, we can mimic the effect on purpose through mindful concentration or meditation. Recent studies using MRI, PET, and SPECT scans have revealed many brain processes that we can harness to benefit ourselves.

Jonah Lehrer, in How We Decide, cited research that reported that 90% of cases of non-specific lower back pain go away with just 7 weeks of rest. That would make rest far more effective than acupuncture or drugs. Perhaps having an active treatment encouraged these participants to continue physical activities that aggravated their back problems. With the expectation that they would be better with acupuncture or drugs, maybe they pushed themselves harder than they should have.

Based on this information, and in the interest of best practices, it seems that the answers to our questions are that Doctors should prescribe seven weeks of rest before moving on to other treatments, and that third-party payers still have little to no call to reimburse for acupuncture. The evidence is not compelling that acupuncture works according to its theories, and the high likelihood of a placebo effect suggests that similar benefits could be achieved through optimism, which is free.

I am interested in any well-done, valid, peer-reviewed studies demonstrating real benefits to acupuncture beyond a placebo effect. Since one in twenty studies may fall prey to a type I error (alpha is usually 0.05), meta-analyses are preferred. Send them my way if you've got 'em.

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