Stimulated by Sun et al 2019.[1]
Ever since I started reading sham controlled acupuncture trials in the early 90’s I have focussed most on the adequacy of the treatment (probably in a self-referential way) compared with the stimulus strength in the sham. I saw Jorge Vas’s trial in OA knee published in the BMJ in 2004,[2] and I was satisfied for the first time that there was an adequate dose of treatment compared with the sham – electroacupuncture (EA) to muscles around the knee versus non-penetrating sham EA. Soon after I pushed my systematic review (SR) mentor, Adrian White, to consider an SR in acupuncture for OA knee in which we considered the adequacy of active treatment and the absence of physiological effect in the sham.[3] We were unable to apply our criteria effectively because so few trials met them, so we went on to write on the subject of dose.[4]
In the biggest data set on acupuncture for chronic pain,[5,6] dose is hard to see. In the first iteration the number of needles and the number treatments came out, with a trend in favour of EA in sham controlled trials.[5] In the update the only thing that remained was the number of treatments, ie more treatments correlated with better outcomes.[6]
So I was very pleased to see this review in Acupuncture in Medicine,[1] which was able to stratify trials by dose criteria and correlate this to outcome. The criteria they used were number of points needled, deqi response, number of treatments per week and the total number of treatments. I was disappointed not to see EA considered in this list, after all two needles with 10mA of EA may well be a considerably bigger dose than 10 needles without any EA. I would also be interested to see where the needles were placed around the knee. EA to needles in Xiyan (ie into the knee joint) are unlikely to stimulate as many high threshold afferents in deep somatic tissue as the same needles placed in nearby muscle tissue.
I was perturbed to see that the Berman trials scored twice as much as the Vas trial,[1] when the former only applied EA to Xiyan, and the latter applied EA to muscles around the knee. Perhaps I am going on too much about this, as the authors did manage to demonstrate a bigger effect in the high dose trials. I should point out that the majority of trials were in the high dose group (n=6) compared with only one in each of the others.
The other major problem is that no account was taken of the relative dose of the active intervention to the control. Some controls involved penetrating needling, but this did not affect the score of the dose, and this dose was being correlated with the effect size of the trial, ie the difference in the effect of the active and control group.
If any potential systematic reviewers are reading this, I must also comment that the total number of treatments is far more important than the frequency of those treatments.
So if I were to try to improve this scoring of dose, I would include marks of EA above 1.5mA, and even more marks for 3mA or above, irrespective of the number of needles. If manual needling only then I am happy with number of needles and deqi response. I would leave out frequency of treatment as long as there was no more than a week between the initial sessions, and I would definitely score for total number of treatments. Then I would add or subtract marks for the physiological activity of the comparator… and soon we will be there – the perfect scoring for a dose of acupuncture (in a trial setting ;-).
References
1 Sun N, Tu JF, Lin LL, et al. Correlation between acupuncture dose and effectiveness in the treatment of knee osteoarthritis: a systematic review. Acupunct Med 2019;6:acupmed2017011608. doi:10.1136/acupmed-2017-011608
2 Vas J, Méndez C, Perea-Milla E, et al. Acupuncture as a complementary therapy to the pharmacological treatment of osteoarthritis of the knee: randomised controlled trial. BMJ 2004;329:1216. doi:10.1136/bmj.38238.601447.3A
3 White A, Foster NE, Cummings M, et al. Acupuncture treatment for chronic knee pain: a systematic review. Rheumatology (Oxford) 2007;46:384–90. doi:10.1093/rheumatology/kel413
4 White A, Cummings M, Barlas P, et al. Defining an Adequate Dose of Acupuncture Using a Neurophysiological Approach – a Narrative Review of the Literature. Acupunct Med 2008;26:111–20. doi:10.1136/aim.26.2.111
5 Vickers AJ, Cronin AM, Maschino AC, et al. Acupuncture for chronic pain: individual patient data meta-analysis. Arch Intern Med 2012;172:1444–53. doi:10.1001/archinternmed.2012.3654
6 Vickers AJ, Vertosick EA, Lewith G, et al. Acupuncture for Chronic Pain: Update of an Individual Patient Data Meta-Analysis. J Pain 2017;19:455–74. doi:10.1016/j.jpain.2017.11.005
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