The review, published in the American Journal of Gastroenterology, found that in some trials, acupuncture seemed to work better than certain medications for IBS. In others, acupuncture was no better than a sham procedure.
"It's difficult to interpret the results of the review," said lead researcher Eric Manheimer, of the Centre for Integrative Medicine at the University Of Maryland School Of Medicine. For now, he said, "I think the evidence is equivocal."
Limited effectiveness in drugs
In many cases, IBS can be managed with diet changes, along with anti-diarrheal medication or, for constipation, laxatives or fibre supplements. There are also a few drugs for the condition – including alosetron (Lotronex) and lubiprostone (Amitiza). Doctors sometimes also prescribe low-dose antidepressants, anti-anxiety medications, or antispasmodics. But drugs are often limited in their effectiveness, and can have side effects.
Two non-drug options – cognitive behavioural therapy and hypnosis – have proven effective for some people in clinical trials. A fairly small number of studies have begun looking at acupuncture.
In their review, the researchers found five clinical trials that tested acupuncture against a sham procedure. None of the five showed that real acupuncture was superior at improving patients' ratings of their symptoms or quality of life.
On the other hand, five trials done in China did find that patients reported bigger gains from acupuncture when it was tested against certain medications – which included certain anti-diarrhoeal, antispasmodic and anti-inflammatory drugs.
But there are limitations to both types of studies, Manheimer said.
Patient expectation plays a role
With the trials that pitted acupuncture against drugs, the patients were recruited at hospitals for traditional Chinese medicine.
"So it's possible that patients' expectations played a role" in acupuncture's higher success odds, Manheimer explained.
With the sham-controlled trials, the study groups tended to be small, which may have limited their ability to pick up small benefits of true acupuncture, the researchers say.
There's also debate over what makes for a good sham version of acupuncture. In some studies, it may involve inserting needles in the skin at sites that are not considered acupuncture points according to traditional Chinese medicine. In others, it means using a dull needle that doesn't penetrate the skin.
Compare acupuncture with other treatments
"It's not clear that they (shams) are all inert," Manheimer said. Some sham acupuncture tactics may have biological effects that are close to the real thing. No one is sure how acupuncture works, but some research suggests the needle stimulation triggers the release of pain- and inflammation-fighting chemicals in the body – even if the acupuncture doesn't strictly follow traditional principles.
In the future, Manheimer said it might be helpful to do trials that compare acupuncture against other treatments, but do it with a more general population of IBS sufferers than the Chinese studies used.
It would also be a good idea, he said, to measure patients' expectations going into the study. That way, researchers can look at whether people who expected to improve were more likely to report benefits from acupuncture.
"This is an interesting study," said Dr Jeffrey M. Lackner of the University at Buffalo School of Medicine in New York, who was not involved in the work.
Teach people CBT principles
In the US, he noted, acupuncture would not be considered a "go-to" IBS treatment. As far as non-drug options, cognitive behavioural therapy (CBT) seems to have the best research evidence to back it up, according to Dr Lackner.
The problem with CBT, though, is availability. "We really need to start developing IBS treatments that are more easily disseminated," he said. That could mean "self-help materials," like books or CDs that teach people CBT principles.
As for acupuncture, Manheimer said that if patients do want to try it, safety and cost would be the other considerations. Acupuncture is generally considered safe, with side effects like bruising at the needle site. The cost can vary widely, but a session would typically start at around R800.
And many patients, Manheimer noted, may have to pay out of pocket.
(Amy Norton, Reuters Health, April 2012)