Manual acupuncture for migraineBMJ 2020; 368 doi: https://doi.org/10.1136/bmj.m1096 (Published 25 March 2020) Cite this as: BMJ 2020;368:m1096
- Heather Angus-Leppan, consultant neurologist1
The same pathways that transmit the caress of a lover can backfire and cause neuropathic pain. This pain is due to damage or disease affecting the sensory systems.1 Migraine is one of the most common and disabling neuropathic pains, affecting at least 10-20% of the population and causing billions of lost days each year. In a linked paper, Xu and colleagues (doi:10.1136/bmj.m697) show that manual acupuncture significantly reduces migraine headaches, compared to both sham acupuncture and usual care.2
One strength of this study is the authors’ choice of control intervention. This is a major hurdle for non-pharmacological studies. Only these authors and one previous study of acupuncture have demonstrated successful masking of the sham procedure.3
Xu and colleagues’ used a non-penetrating needle for sham acupuncture—essential because penetrative sham acupuncture is not inert, and activates pathways involved in pain.4 Choice of control intervention could be one reason why Cochrane meta-analyses of acupuncture studies have found little difference between acupuncture and controls.5 The current study used an additional arm of usual treatment (including advice on lifestyle and self-management), controlling for the therapeutic effects of contact with a clinician, which contribute to strong placebo effects in migraine trials.6 The study achieved 98% retention and reported no serious adverse events.
The effects of acupuncture (and other preventive treatments) are modest (2.1 fewer migraine days per month in the current study), and it is difficult for clinicians to know whether this level of benefit would be noticeable to patients The authors do not discuss the minimally clinically important difference, and statistical significance does not automatically translate to clinical significance. The study period was relatively short (20 weeks) and it is not known whether acupuncture resets sensory pathways for a sustained improvement or whether it must be repeated to maintain its effects. Clearly, resetting the sensory pathway would be better for patients with migraine and longer term studies are now a priority.
Where does acupuncture sit in relation to guidelines for migraine treatments? Xu and colleagues’ study2 does not answer this question, and it is unlikely that any study could, given the many variables to consider (the variety of acupuncture options and the range of pharmacological treatments already in use) and diverse individual preferences and needs. But the study does provide a solid evidence base for a non-pharmacological treatment often dismissed as an unproven complementary therapy. Benefits of acupuncture were less than those associated with recently developed preventive treatments (monoclonal antibodies to calcitonin gene related peptide receptors; 3.7 v 2.1 reduction in migraine days per month)7 but no head-to-head comparisons are currently available.
Acupuncture might be a first choice for people who want to avoid pharmacological treatment, or for those who take several drugs with potential interactions. No interactions have been reported between acupuncture and pharmaceutical agents, and acupuncture is associated with no long term adverse events. Pregnancy was an exclusion criterion in Xu and colleagues’ study, but adverse events in pregnancy have not been reported in the literature. Acupuncture could be a potential treatment for pregnant women who do not want to take drug treatment.
The mechanism of action through which acupuncture relieves migraine is unclear. The experience of pain is complex, and multiple mechanisms could contribute. One possibility is that acupuncture blocks central processing of pain through alternative stimulation, similar to other non-pharmacological pain treatments such as transcutaneous electrical nerve stimulation (in line with the gate control theory of Melzack and Wall).8
Pain sensitive structures in the head and neck connect with cells in the spinal cord, thalamus, and cortex. These same cells also receive input from the limbs, including from established acupuncture points. This convergence might explain acupuncture’s effects.9 Acupuncture also activates the limbic system, important in emotional responses,2 and releases endorphin, a transmitter that potentially reduces pain.10
The cost effectiveness of manual acupuncture and our ability to upscale its use needs further exploration. The practitioners working in this trial were highly skilled, and had five years’ experience. Treatment sessions involved 10 hours of acupuncture in total. This kind of intervention would not be cheap. Further, a fifth of young adults are needle phobic.11 Other options include electrical or automated systems of acupuncture, although further research and development is required, not least to examine whether automated systems are as effective as acupuncture delivered by human contact.
We now have good evidence that acupuncture is an effective treatment for episodic migraine. Given that almost 90% of people with frequent migraine have no effective preventive treatment, acupuncture provides a useful additional tool in our therapeutic armoury. Xu and colleagues’ study helps to move acupuncture from having an unproven status in complementary medicine to an acceptable evidence based treatment.
Competing interests: The BMJ has judged that there are no disqualifying financial ties to commercial companies. The author declares the following other interests: salary is part funded by National Institute for Health Research (NIHR), on advisory board of the Medicines and Healthcare products Regulatory Agency and Sanofi women and epilepsy education board 2018; non pharmacological research grants—Eisai, Royal Free Charity, Epilepsy Action, NIHR. The BMJ policy on financial interests is here: https://www.bmj.com/sites/default/files/attachments/resources/2016/03/16-current-bmj-education-coi-form.pdf.
Provenance and peer review: Commissioned; not peer reviewed.