Reviewing, Race & Sex

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I was spoilt for choice this week! Various papers had the potential to make the cut, but there was no easy way to draw them together, apart from the fact that many were systematic reviews.[1–5] The race and sex from the title refers to a couple of recent experimental papers from the journal Pain, one studying the influence of race on the placebo effect,[6] and the other looking at individual variability and sex differences in CPM (conditioned pain modulation).[7]

CPM – Conditioned Pain Modulation

The first review caught my eye because of the journal name – Archives of Gerontology and Geriatrics. As a medical house officer, I covered a dermatology and a geriatric ward as well as a medical ward. Unfortunately, they were on opposite ends of the Jimmy’s campus, which was almost a mile across. The quickest route was to exit the hospital site and run along the road, which was perfectly straight, then back in through another gate. In the early hours of the morning, the sprint along the road in the cool air would mean that we (the crash team) were all wheezing with cold air induced bronchospasm by the time we got to the ward, and we would have looked in need of resuscitation ourselves – I have so many stories from those days in Jimmy’s!

Anyway, this review included 11 trials, 2 of which were on trigger point acupuncture, and set in Japan.[8,9] I recognised the name of the first author, who has published several papers in Acupuncture in Medicine, indeed one of these two was in our journal, [8] but the other was in a Japanese journal.[9] I clicked on the doi (digital object identifier) anyway and the paper was available to open. I scanned the pages of oriental script and looked at the graphs, then to my surprise I found an abstract in English at the end of the paper – excellent. It was a 4-arm trial (n=44) of standard acupuncture, superficial trigger point needling, deep trigger point needling and non-penetrating sham trigger point needling. The deep trigger point needling group was the only one that showed significant improvement after the three sessions at weekly intervals.

The deep trigger point needling group was the only one that showed significant improvement…

The second review was on recurrent urinary tract infection.[2] I recalled a presentation on this at a BMAS meeting many years ago by Terje Alræk, and of course his trial is one of the 5 included in this review.[10] The review is relatively positive and in quite a prestigious journal – BJOG, which I see has changed its name and created a minor geographical dilemma in the process. I thought it was quite good publicity in the field for acupuncture, and then I read the accompanying editorial, which takes the shine of it somewhat.[11]

Review number three is a positive review on migraine,[3] and includes 28 different RCTs with 2874 patients. I scanned down the list of trials and only recognised a few and noted the absence of the big German trials. So, I checked those included in the 2016 Cochrane review – 22 trials with 4985 participants. There is an important lesson here… wait for it! There was only one trial included in both reviews.

Review number four is on acupuncture for hormone therapy-related side effects in breast cancer patients, and whilst the authors are all from China, none of the included trials are Chinese in this one. In the pooled results they found effects on hot flushes, fatigue and stiffness, but not other outcomes.

Review number five, the last one, includes a network meta-analysis on non-surgical treatments for Achilles tendinopathy.[5] The common node for the network was eccentric exercise (ECC), and acupuncture seemed to come out quite well in comparison to all the other treatments, but the line in the network connecting acupuncture to ECC was rather thin. As I suspected there was only a single trial in that part of the network.[12] The trial was performed in Shanghai and published in 2013. It included 64 patients with chronic Achilles tendinopathy. Local acupuncture was performed using 4 needles (0.35x40mm) inserted 20mm at a shallow angle (15 degrees to the skin). It is not clear whether the needles penetrated the tendon or not – they were described as being ‘around the area’. Treatments were 3 times a week for 8 weeks.

Placebo effects were larger in the patients if the experimenter and participant were of the same sex, but in the healthy subjects the opposite was the case…

What about the effects of placebo in different racial groups? A group from Baltimore recruited 372 participants to take part in their study.[6] Half had temporomandibular disorder (TMD) and the other half were age, sex and race matched healthy controls. The placebo experiment involved a thermal stimulus to the inner forearm, and conditioning via verbal suggestion, manipulation of the stimulus strength and different coloured screens (green and red). White participants had larger placebo effects than black African American (AA) participants, although there was little difference in the TMD patients. Interestingly, effects were larger in the TMD group if the experimenter and participant were of the same sex, but in the healthy subjects the opposite was the case.

Finally, my last paper selection also involves burning the inner forearm, but this time both sides! This is a retrospective experimental study… I know, how can an experimental study be retrospective? Well, the data had already been collected, and the authors then decided to ask a different question of the data that had originally been collected for another purpose. Basically, lots of healthy subjects had been subjected to a raft of quantitative sensory testing, and that was used to find groups that could be compared to assess individual variation and sex differences in CPM (conditioned pain modulation).[7]

The abstract of this paper is almost impossible to assimilate, but the paper is stuffed with lovely colourful graphics that are much easier to understand… so here goes. CPM has a bigger effect if it is less noticeable and not unpleasant. For women who do not register CPM, pain facilitation is less if the conditioning stimulus is less noticeable and not unpleasant. For men who do register CPM, it has a bigger effect if it is not unpleasant. Finally, for men who do not register CPM, resilience is associated with less pain facilitation.

Did you follow that? Well, if it not, wait for the blog webinar and I will try again.


1         Amaral LKB, Souza MB, Campos MGM, et al. Efficacy of conservative therapy in older people with nonspecific low back pain: A systematic review with meta-analysis and GRADE recommendations. Arch Gerontol Geriatr 2020;90:104177. doi:10.1016/j.archger.2020.104177

2         Qin X, Coyle M, Yang L, et al. Acupuncture for recurrent urinary tract infection in women: a systematic review and meta‐analysis. BJOG An Int J Obstet Gynaecol 2020;:1471-0528.16315. doi:10.1111/1471-0528.16315

3         Ou M-Q, Fan W-H, Sun F-R, et al. A Systematic Review and Meta-analysis of the Therapeutic Effect of Acupuncture on Migraine. Front Neurol 2020;11:596. doi:10.3389/fneur.2020.00596

4         Yuanqing P, Yong T, Haiqian L, et al. Acupuncture for Hormone Therapy–Related Side Effects in Breast Cancer Patients: A GRADE-Assessed Systematic Review and Updated Meta-Analysis. Integr Cancer Ther 2020;19:153473542094039. doi:10.1177/1534735420940394

5         Rhim HC, Kim MS, Choi S, et al. Comparative Efficacy and Tolerability of Nonsurgical Therapies for the Treatment of Midportion Achilles Tendinopathy: A Systematic Review With Network Meta-analysis. Orthop J Sport Med 2020;8:232596712093056. doi:10.1177/2325967120930567

6         Okusogu C, Wang Y, Akintola T, et al. Placebo hypoalgesia: racial differences. Pain 2020;161:1872–83. doi:10.1097/j.pain.0000000000001876

7         Firouzian S, Osborne NR, Cheng JC, et al. Individual variability and sex differences in conditioned pain modulation and the impact of resilience, and conditioning stimulus pain unpleasantness and salience. Pain 2020;161:1847–60. doi:10.1097/j.pain.0000000000001863

8         Itoh K, Katsumi Y, Hirota S, et al. Effects of Trigger Point Acupuncture on Chronic Low Back Pain in Elderly Patients – a Sham-Controlled Randomised Trial. Acupunct Med 2006;24:5–12. doi:10.1136/aim.24.1.5

9         Itoh K, Katsumi Y. Effect of Acupuncture Treatment on Chronic Low Back Pain with Leg Pain in Aged Patients-A Controlled Trial about Short-term Effects of Trigger Point Acupuncture-. Zen Nihon Shinkyu Gakkai zasshi (Journal Japan Soc Acupunct Moxibustion) 2005;55:530–7. doi:10.3777/jjsam.55.530

10       Alraek T, Soedal LIF, Fagerheim SU, et al. Acupuncture Treatment in the Prevention of Uncomplicated Recurrent Lower Urinary Tract Infections in Adult Women. Am J Public Health 2002;92:1609–11. doi:10.2105/AJPH.92.10.1609

11       Cartwright R, Miotla P. Pinning down the evidence for acupuncture for recurrent urinary tract infection. BJOG An Int J Obstet Gynaecol Published Online First: 13 July 2020. doi:10.1111/1471-0528.16360

12       Zhang B, Zhong L, Xu S, et al. Acupuncture for chronic achilles tendnopathy: A randomized controlled study. Chin J Integr Med 2013;19:900–4. doi:10.1007/s11655-012-1218-4

Declaration of interests MC