Biological Implausibility Aside, Acupuncture Works

A large meta-analysis has shown that acupuncture's benefits can't be fully attributed to placebo effect, raising the question throughout Western medicine: Why?


Stringer China/Reuters

While in China as a correspondent for the New York Times, journalist James Reston underwent an emergency appendectomy. The entire process, which he described in a 1971 feature, was unsurprisingly foreign, but more curious -- and intriguing -- was his doctor's method of relieving his post-operative pain:

Li Chang-yuan, doctor of acupuncture at the hospital, with my approval, inserted three long, thin needles into the outer part of my right elbow and below my knees and manipulated them in order to stimulate the intestine and relieve the pressure and distension of the stomach.

That sent ripples of pain racing through my limbs and, at least, had the effect of diverting my attention from the distress in my stomach.

With these words, acupuncture began its ascent to the American mainstream. Accepted as perhaps more credible than other forms of alternative medicine, it's nonetheless been unable to rise above the inevitable suspicion to which all holistic treatments are subject: that they are, at best, nothing more than fancy ways of invoking the placebo effect and, at worst, scams.

The main argument in support of acupuncture echoes Reston's own account: at a certain point, all that really matters is that the pain goes away. And in fact, there is evidence to suggest that acupuncture can be an effective way of relieving lower back pain, knee osteoarthritis, and migraines. However, most of these studies also show that sham acupuncture -- being poked with randomly with needles, or even just being tricked into thinking you've been poked -- is just as effective. The general consensus has been that a placebo effect , albeit one bolstered by 2000 years of history, is indeed the main mechanism behind acupuncture's ability to provide pain relief. In an Atlantic article on alternative medicine last year, Steven Salzberg, a researcher at the University of Maryland at College Park told David Freedman that "Acupuncture is just a 3,000-year-old relative of bloodletting."

But new, large study out of Memorial Sloan-Kettering Cancer Center, published in the Archives of Internal Medicine, cautiously suggests that there is indeed something more to acupuncture. A meta-analysis of 18,000 patients from 29 randomized controlled studies, it found that the treatment was more effective than controls in relieving back and neck pain, osteoarthritis, chronic headache, and shoulder pain. Significantly, it also found that real acupuncture was more effective than shams.

Putting their results into context, the authors of the study explain that for a pain rating of 60 on a 100-point scale, follow-up scores decreased to around 43 for those had received no treatment, 35 for those who had received fake treatment, and 30 for those who received acupuncture. This translates into a 50 percent reduction in pain for the acupuncture patients, and only 30 and 42.5 percent reductions for the control and placebo groups, respectively.

It is impossible to measure pain objectively (Radiolab did a great piece on this last week), and the difference in pain reduction between sham and true acupuncture, though statistically significant, was small. But the authors' methodical elimination of biases, coupled with their massive sample size, give weight to their findings. And, as Freedman wrote last year, even a small boost in effectiveness over placebos is acceptable by Western standards:

"Mainstream medicine uses the placebo effect all the time," says Ted Kaptchuk, a Harvard researcher who studies the impact of placebos. "Doctors don't tell you the drug they're giving you is barely better than a placebo. They all spin." To be approved by the FDA, a drug has to do better than a placebo in studies--but most approved drugs do only a little better, and for many drugs the evidence is mixed.

The bigger trouble, if acupuncture's effectiveness can't be explained by the placebo effect, may be that we don't have a good alternative for how it might work. The authors of this new study acknowledge that a lot of the controversy surrounding acupuncture comes from "its lack of biological plausibility, and its provenance in theories lying outside of biomedicine." Attempts have been made to look beyond traditional Chinese concepts of balanced qi and body channels to theories about triggering the release endorphins and the anatomic locations of loose connective tissues, but no robust evidence exists for any of the proposed "plausible" explanations.

The lack of a physiologic rationale may be enough to stop some doctors from referring their patients to an acupuncturist. And the treatment can get pricey, especially in cases that require multiple sessions, and it is not currently covered by Medicare or Medicaid. But in an accompanying editorial, Dr. Andrew Avins points out that compassionate care is also associated with improved health outcomes in ways that we don't fully understand. He asks, "Should the lack of biological plausibility lead us to reject compassion and empathy as a means to help improve our patients' health?"

As for the new information this study gives us, its authors point out that "the clinical decision made by physicians and patients is not between true and sham acupuncture but between a referral to an acupuncturist or avoiding such a referral," and it is here that their results most strongly support acupuncture's effectiveness. Even if there are a lot of placebo-like factors influencing the success of true acupuncture, it did, after all, help the pain go away.