A recent meta-analysis of acupuncture studies for chronic pain by Vickers et al is getting a great deal of press. The authors’ conclusions are:

Acupuncture is effective for the treatment of chronic pain and is therefore a reasonable referral option. Significant differences between true and sham acupuncture indicate that acupuncture is more than a placebo. However, these differences are relatively modest, suggesting that factors in addition to the specific effects of needling are important contributors to the therapeutic effects of acupuncture.

News reports generally reflect this conclusion – acupuncture works, but mostly (although not entirely) through placebo effect, but that’s OK.

I took a close look at the study and find that the authors display considerable pro-acupuncture bias in their analysis and discussion. They clearly want acupuncture to work. That aside, the data are simply not compelling, and the authors, in my opinion, grossly overcall the results, which are compatible with the conclusion that there are no specific effects to acupuncture beyond placebo.

The meta-analysis looked at 29 randomized clinical trials of acupuncture in back pain, neck pain, headache, and osteoarthritis, involving both sham and no-acupuncture controls. The differences between acupuncture and no-acupuncture were large, reflecting an absolute reduction in pain of about a 30% (50% relative reduction). However, the authors acknowledge:

Because the comparisons between acupuncture and no-acupuncture cannot be blinded, both performance and response bias are possible.

In other words – the unblinded comparison between acupuncture and no acupuncture is entirely overwhelmed by bias and completely useless. The no acupuncture control groups involved patients continuing to receive usual care (whatever they were already receiving that was not effective, or sometimes just being told not to get acupuncture). This was not a comparison to any specific medical intervention. In other words, the subjects were aware they were receiving no treatment.