Stimulated by Lee et al 2024.[1]
SR – systematic review
NMA – network meta-analysis
KIOM – Korean Institute of Oriental Medicine
SATS – sham acupuncture therapy sham point
SATV – sham acupuncture therapy verum point
RR50 – responder rate defined as a 50% reduction in headache days per month– key to acronyms
It is a year ago since I highlighted the last such paper (see: Does sham point location matter 2),[2] and this is the third SR with NMA in the series from KIOM with the same lead author – Boram Lee. The first appeared in September 2023, a few months before the first (see: Does sham point location matter).[3]
This time the focus is on sham controlled trials of acupuncture in migraine and the thesis is again that the location of points used in the sham treatment group may influence outcomes (SATS vs SATV).
The not so hidden assumption here is that acupuncture points exist and have specific effects. Of course, I would say that the evidence supporting those assumptions is rather limited from a strictly physiological perspective. As I have said previously, I think the stimulus strength is likely to be more important than the precise intra-segmental location of that stimulus. Other aspects that may well be important when considering the difference between SATS and SATV in controlled trials relates to the beliefs and expectations of the unblinded therapist.
Again, we have the main question of this paper relying on a single node in the NMA that is connected by a single thin line to the rest of the network, ie very few data points and only a single direct comparator for that node. Networks are more stable (have higher consistency) when each node has more than one direct comparator. Consistency refers to the agreement between direct and indirect comparisons in the network.
The abstract of this paper tells us that 18 studies were included with a total of 1936 participants, but it does not mention that the data from only 13 of the latter is what connects the SATV node to the rest of the network. In short, the main argument and conclusion of this paper essentially relies on the results of a single small sham controlled trial from almost 2 decades ago.[4] This study compared 15 women with menstrally related migraine who received acupuncture with 13 who received a non-penetrating sham at the same points. The Streitberger needle was used in the sham group. There is also mention of a cap to keep the sham devices in place over the hair, but it is not clear whether or not sham devices were used in the real acupuncture group as well. Nine sessions of acupuncture or sham were applied, with 3 treatments per menstrual cycle. There was no difference between the groups in the outcomes measured in this trial (attack frequency, migraine days, headache intensity, drug use).
Despite there being no differences in outcomes in the original trial, when this small group (n=13) receiving SATV was added to the network, it could only be attached relative to the true acupuncture node. There was a very tiny difference in the mean headache intensity at the time point used for outcomes in this NMA from the original trial, which was in favour of SATV over real acupuncture. This meant that SATV was marginally ahead of real acupuncture, but because the real acupuncture node had expanded from 15 in the original trial to 775 in the NMA, this small difference made it look as though SATV was the best intervention and significantly better than no treatment, despite there being no real effect, or even change from baseline, in the original trial.
SATV was not significantly better than SATS in the NMA, but there was a trend in favour of SATV. But this trend was entirely artificial since the SATS node was made up of penetrating needling, which has shown substantial effects in the largest trials of acupuncture in migraine,[5,6] both of which were included in this NMA.
In case I have not been clear here, penetrating SATS (all trials in this NMA used penetrating needling for the sham in this category) has substantial effects in migraine outcomes. For example, an RR50 of 53% in the first large RCT.[5] SATV had no effect in the original trial, yet it comes out on top in this NMA.
This is the 3rd paper based on NMAs in which the conclusions suggest SATV is superior to SATS and therefore should not be used in RCTs testing acupuncture. Each one has involved a single paper representing the SATV node in the NMA with the data point number diminishing each time (159[3] to 33[2] to 13[1]). I guess these papers will eventually be combined into a PhD thesis with a neat and consistent conclusion about the superiority of SATV over SATS and thus the specificity of real acupuncture points as opposed to sham points.
My conclusion would be somewhat different and run along the lines that physiologically dubious interpretations should not be made from thin lines connecting isolated nodes in NMAs. I genuinely hope Boram’s PhD examiners don’t read this blog, or at least not until after she passes her viva.
References
1 Lee B, Kwon C-Y, Lee HW, et al. Does the outcome of acupuncture differ according to the location of sham needling points in acupuncture trials for migraine? A systematic review and network meta-analysis. Front Med. Published Online First: 20 December 2024. doi: 10.1007/s11684-024-1109-z
2 Lee B, Kwon C-Y, Lee HW, et al. Different Outcomes According to Needling Point Location Used in Sham Acupuncture for Cancer-Related Pain: A Systematic Review and Network Meta-Analysis. Cancers. 2023;15:5875. doi: 10.3390/cancers15245875
3 Lee B, Kwon C-Y, Lee HW, et al. Needling Point Location Used in Sham Acupuncture for Chronic Nonspecific Low Back Pain: A Systematic Review and Network Meta-Analysis. JAMA Netw Open. 2023;6:e2332452. doi: 10.1001/jamanetworkopen.2023.32452
4 Linde M, Fjell A, Carlsson J, et al. Role of the Needling per se in Acupuncture as Prophylaxis for Menstrually Related Migraine: A Randomized Placebo-Controlled Study. Cephalalgia. 2005;25:41–7. doi: 10.1111/j.1468-2982.2004.00803.x
5 Linde K, Streng A, Jürgens S, et al. Acupuncture for patients with migraine: a randomized controlled trial. JAMA. 2005;293:2118–25. doi: 10.1001/jama.293.17.2118
6 Diener H-C, Kronfeld K, Boewing G, et al. Efficacy of acupuncture for the prophylaxis of migraine: a multicentre randomised controlled clinical trial. Lancet Neurol. 2006;5:310–6. doi: 10.1016/S1474-4422(06)70382-9
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