Wednesday January 21 2009
'Sham' acupuncture seemed to work just as well as the traditional kind
The Daily Telegraph reported today that “even 'fake' acupuncture reduces the severity of headaches and migraines”. It said that a major review of acupuncture studies has found that the treatment can help people who suffer from headache and migraine, “even when the needles are put in the 'wrong' place”. It said that the success of both traditional and ‘sham’ acupuncture suggested a strong placebo effect.
This thorough systematic review looked at acupuncture used for preventing tension headache or migraine. Acupuncture was found to reduce the frequency of headaches compared to taking no preventative measures (such as drugs or relaxation techniques). The review also found that traditional and sham acupuncture seemed to have the same success in preventing the onset of migraines.
These results suggest that acupuncture can potentially reduce the frequency of migraine or tension headaches. However, a systematic review is subject to the quality of the studies that it looks at, and these studies were of varying quality. Additionally, the review does not suggest that acupuncture is better than medicine at treating attacks, and there is limited evidence comparing acupuncture to preventive medicines.
Where did the story come from?
Klaus Linde from the University of Munich, Germany and colleagues from universities and medical centres in Italy, the US and UK carried out the research. The work was published as two papers – Acupuncture for Migraine Prophylaxis and Acupuncture for Tension-Type Headache – in the Cochrane Database of Systematic Reviews.
What kind of scientific study was this?
These two systematic reviews collated and assessed the evidence for the use of acupuncture in treating headaches. Their aim was to investigate whether acupuncture is more effective than routine care or when no preventative measures are taken. They also investigated whether acupuncture is as effective as other interventions in reducing the frequency of headache. They also looked at whether traditional acupuncture is more effective than ‘sham’ acupuncture (where needles are inserted into incorrect acupuncture points or do not penetrate the skin). The use of acupuncture has been dubbed ‘controversial’, but its supporters suggest that it is effective at treating pain through a range of physiological and psychological actions.
The researchers searched a number of medical literature databases for all relevant randomised controlled trials (RCTs) that had been published up until January 2008. To be eligible for inclusion, the studies had to have followed participants for at least eight weeks after treatment, to have compared the effects of acupuncture with other preventative interventions, sham acupuncture, or a control (including no treatment or only treating the acute migraine episodes or tension headaches). In the studies, all participants had to have been diagnosed with migraine or tension-type headache.
Identified studies were assessed for their quality. The researchers then extracted information on the interventions used, patient groups (exact diagnoses and headache classifications used), and methods and results. They were mainly interested in response to treatment (defined as at least 50% reduction in headache frequency). They also looked at the number of days people were affected by migraine or headaches, as well as their frequency, pain intensity and use of painkillers. Where possible, the researchers pooled the results from the individual trials.
What were the results of the study?
For the analysis of acupuncture for migraine, 22 trials met the inclusion criteria, with a total of 4,419 participants. There were on average 201 people in each trial, and the trials came from various European and Scandinavian countries. Six of the trials compared acupuncture to control (no preventative treatment or routine care). These found that people who had acupuncture had a significantly higher response rate and fewer migraines three to four months after treatment compared with those in the control groups. One longer-term study found that both effects were still significant more than six months after treatment.
The researchers found 14 trials that compared traditional acupuncture to a sham intervention. The effect of acupuncture varied considerably between individual trials. When the results were pooled, both interventions were found to improve migraine, but there was no significant difference between traditional and sham acupuncture for any outcome.
In four trials that compared acupuncture to preventative measures (mainly non-pharmacological, physiotherapy, relaxation. etc.), the frequency of headaches improved significantly with acupuncture with fewer adverse effects. However, there was no difference in response.
For the analysis of acupuncture for tension headaches, 11 trials were identified with a total of 2,317 participants (averaging 62 people per trial). Two large RCTs compared acupuncture to control (no preventative treatment or routine care). Acupuncture was found to cause a statistically significant improvement in response compared to no preventative treatment. However, these effects were only investigated for up to three months after treatment.
A meta-analysis of five out of six trials that compared acupuncture to sham acupuncture for tension headache showed there to be a significant small benefit of traditional acupuncture over sham acupuncture. The researchers say that the four trials that compared acupuncture to other preventative treatments (mostly non-pharmacological) had methodological limitations and were difficult to interpret.
What interpretations did the researchers draw from these results?
The authors conclude there is "consistent evidence" that acupuncture can provide additional benefit to routine care (i.e. giving no preventative treatment and only treating the acute migraine episode). They say that it is "at least as effective or possibly more effective" than preventative drug treatment.
They also say there is no evidence that traditional acupuncture is any more effective than sham acupuncture for migraine. For tension-type headaches, they say there is now evidence that acupuncture could be "a valuable non-pharmacological tool" for the prevention of episodic or chronic tension headache.
What does the NHS Knowledge Service make of this study?
These are thorough systematic reviews, and are likely to have identified all the major clinical trials that looked at the use of acupuncture for tension headache or migraine. The findings suggest a potential role for acupuncture in reducing the frequency of migraine or tension headaches. There are some points to consider:
- The trials varied considerably in their quality, methods, interventions (particularly for sham interventions), patients, times when the treatment was administered (e.g. as a preventative measure or for treating an acute episode), and the outcomes that were measured. This can cause some difficulty in interpreting the results, particularly for answering the question of whether traditional acupuncture is any more effective than sham acupuncture.
- The researchers have given a clear interpretation of the current evidence, and discuss possible physiological and psychological reasons for their findings, but have not made statements such as all headaches are "in the mind", as several news reports claimed. The researchers also do not offer the placebo effect as a conclusive explanation for the effectiveness of both sham and traditional acupuncture; they only discuss it. In fact, the researchers acknowledge the limitations of the studies and the difficulty in interpreting several of the studies.
- The main body of evidence compares acupuncture to either no preventative treatment or to usual care. There appear to be very few studies that compare acupuncture to migraine drugs (e.g. beta-blockers), and whether the use of these was included in ‘usual care’ is unclear. Only a few trials compared to prophylaxis, and those that did were compared to non-pharmacological treatments, e.g. physiotherapy, relaxation techniques, etc. Therefore further research in this area is needed, and any interpretation that acupuncture is better than pharmacological preventative drugs, e.g. beta blockers, should be made with caution.
- Although some of the trials examined acute episodes, on the basis of this research, the use of acupuncture has principally been considered as a preventative measure against future episodes of migraine or headache. The review has not concluded, and does not suggest, that acupuncture is as effective as analgesic and other treatments for acute, severe headaches.