A New Acupuncture Study Is One of the Worst Studies I Have Ever Seen
A new meta-analysis published in PLoS ONE comparing acupuncture and drugs for the treatment of chronic constipation is one of the worst studies I have ever seen. Chinese researchers from Longhua District Central Hospital in Shanghai, China found that "acupuncture is more effective than drugs in improving chronic constipation and has the least side effects," but they came to that conclusion by employing misleading tactics intended to produce that result.
Meta-analyses statistically combine the results of multiple studies in order to ascertain the state of scientific evidence for a certain topic. When performed honestly and without bias, a meta-analysis can accurately reflect the published literature. However, it can also be easily manipulated to reach a desired conclusion.
That seems to be exactly what's going on here. The researchers sought to compare a variety of laxative drugs, including polyethylene glycol, lactulose, linaclotide, lubiprostone, and bisacodyl, with acupuncture for the treatment of constipation through what's called a "network" meta-analysis. Because there are no studies that actually compare acupuncture and laxatives with the same protocol and study group, the researchers examined a bunch of studies independently, and compared the proportion of patients who experienced "overall symptom improvement" for each treatment. The researchers' analysis included 40 studies When statistically combining the results of the studies, the researchers found acupuncture to be "more effective than drugs in treating chronic constipation with nearly no side effects."
However, the analysis was completely bogus. For starters, the researchers compared apples to rotten apples. The vast majority of the laxative studies were double-blind, randomized, placebo-controlled trials published in peer reviewed journals. On the other hand, all of the acupuncture studies were unblinded, four were not peer-reviewed, five were published in questionable journals like the Shanghai Journal of Acupuncture and Moxibustion, and all were based in China, which is notoriously friendly to acupuncture and alternative medicine. Thus, it's no surprise that acupuncture showed stronger results in those studies.
Second, the researchers reported that acupuncture had no side effects because nine of the ten acupuncture studies didn't even report side effect data. Instead, they justified their finding by casually stating, "Acupuncture had the fewest side effects, as there are not many known side effects." They apparently neglected to read numerous studies which documented side effects like bleeding, bruising, or dizziness in roughly 7.4 percent of cases, as well as rare, but serious events like traumatic lesions.
Lastly, "overall symptom improvement" is a metric intended to mislead. The researchers neglected to measure how much symptoms improved, only if they improved at all. So, for example, a reduction in symptoms by 10% in an acupuncture study would receive just as much weight as a 70% reduction in symptoms in a laxative study.
The researchers concluded that quality studies are still needed to support their finding that acupuncture outperforms laxative drugs for treating constipation, but those studies will almost certainly never be done. If they were, the evidence would show that acupuncture doesn't actually work.
The present study is a textbook example of what acupuncture proponents do to give their profession a veneer of scientific legitimacy: publish a crappy study in a journal with lax peer review. No doubt this shoddy, dishonest meta-analysis will be used to trick laypersons to seek acupuncture to cure their chronic constipation, which is a growing problem in the United States and results in 700,000 trips to hospital emergency departments each year. By publishing this study, PLoS is complicit in promoting pseudoscience and leading people away from effective, evidence-based treatments for chronic constipation.
Source: Zhu L, Ma Y, Deng X (2018) Comparison of acupuncture and other drugs for chronic constipation: A network meta-analysis. PLoS ONE 13(4): e0196128. https://doi.org/10.1371/journal.pone.0196128