Stimulated by Liao et al 2023.[1]
MDD – major depressive disorder
key to acronyms
WMA – Western medical acupuncture
TCM – traditional Chinese medicine
BPI – brief pain inventory
RCT – randomised controlled trial
GRADE – Grading of Recommendations, Assessment, Development and Evaluation (a method of grading the quality or ‘certainty’ and strength or ‘effect size’ of evidence in healthcare)
ES – effect size
HAM-D – Hamilton depression rating scale
BDI – Beck depression inventory
This is a small cross-over trial without a particularly dramatic result, but it appealed to me because whilst the premise of the trial seems to be generally accepted in the acupuncture world (although not my me), it is rarely actually tested. It is published in the journal Brain, Behaviour and Immunity, which has an impact factor of just under 20. The authors of the trial hypothesised that pain specific acupuncture points would alleviate pain more than depression specific acupuncture points and vice versa in patients with comorbid chronic pain and major depressive disorder (MDD).
Any readers who have been taught WMA by the BMAS will be instantly sceptical of the likely veracity of this hypothesis, but I guess the majority of TCM trained practitioners may not have ever considered doubting it. Having said that, the interventions are set protocols based on points used in RCTs, rather than using an individualised approach.
Each protocol was applied in 12 sessions over 6 weeks followed by a 2-week washout period and a further 12 sessions over 6 weeks of the other protocol. 47 patients with MDD and chronic pain of 4 or more out of 10 (on item 5 of the BPI long form) were randomised to start with one or other of the protocols.
The MDD protocol involved 18 needles with 10 in the head and 2 in each limb, and the pain protocol involved 26 needles, most of which were in big muscles. So, from a WMA perspective there is a difference in dose, but RCTs in the past have rarely been able to demonstrate differences in acupuncture dose. We see dose demonstrated more often in laboratory experiments, but only in certain physiological parameters, and rarely if ever in a linear dose response relationship. The latter, incidentally, gives an intervention a higher score in the GRADE system, something that appears to give pharmaceuticals an advantage over physical medicine interventions.
By the end of the second phase of the cross-over design there were only 29 patients remaining, so the rate of attrition was a lot higher than would be ideal at over nearly 40%. In addition to this, the authors’ power calculation suggested they needed 75 to detect a difference in effect size (ES) of 0.6. Since the ES for acupuncture over sham in chronic pain is typically 0.2, they were really pushing their luck here!
It won’t surprise you to hear that this RCT did not show any statistically significant differences between interventions in the main analysis (HAM-D for MDD and BPI for chronic pain). However, it did throw up one or two significant findings for us to consider.
First of all, the pain protocol was significantly better than the depression protocol in the first phase of the trial (ie before the crossover) when considering the BPI. There was also a trend in favour of the pain protocol when considering the effect on MDD, plus one outcome (BDI) that just reached statistical significance in favour of the pain protocol. The remission rate was 20% and the treatment response rate was 35% in the pain protocol group compared with 4.3% and 17.4% in the depression protocol group.
Secondly, the authors estimated carryover effects beyond the 2-week washout period. They concluded that the effect on depression carried over but that the effect on pain did not. I think that is unlikely to be the case, but that their measures simply did not detect any carryover for pain.
They also measured changes in inflammatory cytokines, expecting to see differences based on the treatment of pain or depression, but of course there was huge variability in this data and so no chance of seeing any differential effect, even if there was one.
What does the WMA approach offer TCM acupuncture research? It would have told you not to waste your time on a question like this in the first place, but having done so, it will suggest that you may have just glimpsed a dose effect, and you should really seriously question any ideas of point specificity.
References
1 Liao H-Y, Kumaran Satyanarayanan S, Lin Y-W, et al. Clinical Efficacy and Immune Effects of Acupuncture in Patients with Comorbid Chronic Pain and Major Depression Disorder: A Double-Blinded, Randomized Controlled Crossover Study. Brain Behav Immun 2023;:S0889-1591(23)00073-9. doi:10.1016/j.bbi.2023.03.016
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