Placebo control groups are easy to arrange in the context of conventional drug trials, because the treatment group can, say, receive a pill with the active ingredient and the placebo control group can receive an identical-looking pill without the active ingredient. Or the treatment group can receive an injection of the active drug and the placebo control group can receive an injection of saline. Unfortunately, there was no similarly obvious placebo replacement for acupuncture.
Gradually, however, researchers began to realize that there were two ways of making patients believe that they were receiving real acupuncture, when they were in fact receiving fake acupuncture. One option was to needle patients to only a minimal depth, as opposed to the centimetre or more that most practitioners would use. The purpose of this superficial needling was that it seemed like the real thing to patients who had not previously experienced genuine acupuncture, but according to the Chinese theory it should have no medical benefit because the needles would not reach the meridian. Therefore researchers proposed studies in which a control group would receive superficial needling, while a treatment group would receive real acupuncture. Both groups would receive similar levels of placebo benefit, but if real acupuncture has a real physiological effect then the treatment group should receive a significant extra benefit beyond that received by the control group.
Another attempt at placebo acupuncture involved needling at points that are not acupuncture points. Such points traditionally have nothing to do with a patient’s health. This misplaced needling would seem like genuine acupuncture to new patients, but according to the Chinese theory misplaced needling should have no medical benefit because it would miss the meridians. Hence, some trials were planned in which the control group would receive misplaced needling and the treatment group would receive genuine acupuncture. Both groups would receive the benefit of the placebo effect, but any extra improvement in the treatment group could then be attributed to acupuncture.
These two forms of placebo acupuncture, misplaced and superficial, are often termed sham needling. During the 1990s, sceptics pushed for a major reassessment of acupuncture, this time with placebo-controlled clinical trials involving sham needling. For many acupuncturists, such research was redundant because they had seen how their own patients had responded so positively. They argued that the evidence in favour of their treatment was already compelling. When critics continued to demand placebo-controlled trials, the acupuncturists accused them of clutching at straws and of being prejudiced against alternative medicine. Nevertheless, those medical researchers who believed in the authority of the placebo-controlled trial refused to back down. They continued to voice their doubt and argued that acupuncture would remain a dubious therapy until it had proved itself in high-quality clinical trials.
Those demanding proper acupuncture trials eventually had their wish granted when major funding enabled dozens of placebo-controlled clinical trials to take place in Europe and America throughout the 1990s. Each trial was to be conducted rigorously in the hope that the results would shed new light on who was right and who was wrong. Was acupuncture a miracle medicine that could treat everything from colour blindness to whooping cough, or was it nothing more than a placebo?
Acupuncture on trial
By the end of the twentieth century a new batch of results began to emerge from the latest clinical trials on acupuncture. In general these trials were of higher quality than earlier trials, and some of them examined the impact of acupuncture on conditions that had not previously been tested. With so much new information, the WHO decided that it would take up the challenge of summarizing all the research and presenting some conclusions.
Of course, the WHO had already published a summary document in 1979, which had been very positive about acupuncture’s ability to treat more than twenty conditions, but they were keen to revisit the situation in light of the new data that was emerging. The WHO team eventually took into consideration the results from 293 research papers and published their conclusions in 2003 in a report entitled Acupuncture: Review and analysis of reports on controlled clinical trials. The new report assessed the amount and quality of evidence to support the use of acupuncture for a whole series of conditions, and it summarized its conclusions by dividing diseases and disorders into four categories. The first category contained conditions for which there was the most convincing evidence in favour of using acupuncture and the fourth contained conditions for which the evidence was least convincing:
Conditions ‘for which acupuncture has been proven — through controlled trials — to be an effective treatment’ — this included twenty-eight conditions ranging from morning sickness to stroke.
Conditions ‘for which the therapeutic effect of acupuncture has been shown but for which further proof is needed’ — this included sixty-three conditions ranging from abdominal pain to whooping cough.
Conditions ‘for which there are only individual controlled trials reporting some therapeutic effects, but for which acupuncture is worth trying because treatment by conventional and other therapies is difficult’ — this included nine conditions, such as colour blindness and deafness.
Conditions ‘for which acupuncture may be tried provided the practitioner has special modern medical knowledge’ — this included seven conditions, such as convulsions in infants and coma.
The 2003 WHO report concluded that the benefits of acupuncture were either ‘proven’ or ‘had been shown’ in the treatment of ninety-one conditions. It was mildly positive or equivocal about a further sixteen conditions. And the report did not exclude the use of acupuncture for any conditions. The WHO had given acupuncture a ringing endorsement, reinforcing their 1979 report.
It would be natural to assume that this was the final word in the debate over acupuncture, because the WHO is an international authority on medical issues. It would seem that acupuncture had shown itself to be a powerful medical therapy. In fact, the situation is not so clear cut. Regrettably, as we shall see, the 2003 WHO report was shockingly misleading.
The WHO had made two major errors in the way that it had judged the effectiveness of acupuncture. The first error was that they had taken into consideration the results from too many trials. This seems like a perverse criticism, because it is generally considered good to base a conclusion on lots of results from lots of trials involving lots of patients — the more the merrier. If, however, some of the trials have been badly conducted, then those particular results will be misleading and may distort the conclusion. Hence, the sort of overview that the WHO was trying to gain would have been more reliable had it implemented a certain level of quality control, such as including only the most rigorous acupuncture trials. Instead, the WHO had taken into consideration almost every trial ever conducted, because it had set a relatively low quality threshold. Therefore, the final report was heavily influenced by untrustworthy evidence.
The second error was that the WHO had taken into consideration the results of a large number of acupuncture trials originating from China, whereas it would have been better to have excluded them. At first sight, this rejection of Chinese trials might seem unfair and discriminatory, but there is a great deal of suspicion surrounding acupuncture research in China. For example, let’s look at acupuncture in the treatment of addiction. Results from Western trials of acupuncture include a mixture of mildly positive, equivocal or negative results, with the overall result being negative on balance. By contrast, Chinese trials examining the same intervention always give positive results. This does not make sense, because the efficacy of acupuncture should not depend on whether it is being offered in the Eastern or Western hemisphere. Therefore, either Eastern researchers or Western researchers must be wrong — as it happens, there are good reasons to believe that the problem lies in the East. The crude reason for blaming Chinese researchers for the discrepancy is that their results are simply too good to be true. This criticism has been confirmed by careful statistical analyses of all the Chinese results, which demonstrate beyond all reasonable doubt that Chinese researchers are guilty of so-called publication bias.