Inspired by Cao et al 2023.[1]
EA – electroacupuncture
key to acronyms
IR – insulin resistance
PCOS – polycystic ovary syndrome
BMI – body mass index
HOMA-IR – homeostatic model assessment of insulin resistance
AUC – area under curve
I have a blog category for PCOS, but the last post on the topic was over 2 years ago. This paper is a post hoc analysis of a prior trial. That means nobody thought about doing it beforehand… but only after they had seen the data.
The original trial was highlighted here: EA vs metformin for IR in PCOS 2021.[2] It was a 3-armed double dummy trial comparing EA and metformin in women with PCOS and IR. Metformin seemed to be significantly better, but there was a marked baseline difference between groups, and the results seemed difficult to interpret with confidence.
This new analysis of the data divides the group into lean and obese women and presents the results separately for these groups. The cut off used was a BMI of 24, so those with a BMI of 24 or greater were placed in the obese group (overweight and obese group) and those under 24 were placed in the lean group.
HOMA-IR was the primary outcome in the original trial as well as in this reanalysis of the data based on baseline weight categories. The baseline difference I was worried about in the original trial reappeared in the obese group, and almost reached the normal standard for statistical significance. In the lean group there were no baseline differences of note.
EA performed as well as metformin in the lean group, although the double dummy seemed to perform just as well as the active groups in terms of mean group reductions in HOMA-IR. In the obese group the mean reduction in HOMA-IR at 4 months was significantly larger in the metformin group; however, the absolute values of HOMA-IR at 4 months were the same, and all the change could be attributed to a levelling up the baseline difference. This makes the results rather hard to interpret in the same way as for the total data set in the previous report.
It is interesting to note that the group mean value for HOMA-IR was in the normal range (<2.5) in only one group at the 7-month point – the lean EA group. This was true of both EA and metformin groups at the 4-month point in the lean cohort. The obese cohort group means were always markedly above the normal range.
One of the many secondary outcomes was glucose AUC from an oral glucose tolerance test. This appeared to be consistently reduced by EA in both lean and obese groups when compared with the effect of metformin. However, at the 4 month point the mean reduction in the lean double dummy group was numerically larger than in the lean EA group. This was not the case in the obese group, in which EA reduced glucose AUC significantly more than both sham acupuncture plus metformin and sham acupuncture plus placebo metformin.
I should note that the sham acupuncture did involve superficial needling at 2 points in the shoulder area and no EA stimulation, whereas the true EA group received both EA and manual acupuncture to abdominal and leg points (14 needles in total – 4 abdominal EA, 4 leg EA, 4 leg manual, and LI4 bilaterally). I should also remind readers that the treatment course was rather intensive, with 48 sessions over 4 months ie ~3x per week.
Whilst I was reviewing my past blog posts in the PCOS category, I was reminded of an ongoing trial,[3] which I described in a previous blog: Should I read a protocol? The protocol was published in 2020, so I decided to look it up on ClinicalTrials.gov to see how far things had progressed. It is estimated to finish at the end of this month. No doubt it will be another one to add to my PCOS category.
Reference
1 Cao J, Nie G, Dai Z, et al. Comparative effects of acupuncture and metformin on insulin sensitivity in overweight/obese and lean women with polycystic ovary syndrome and insulin resistance: a post hoc analysis of a randomized trial. Front Med. 2023;10:1232127.
2 Wen Q, Hu M, Lai M, et al. Effect of acupuncture and metformin on insulin sensitivity in women with polycystic ovary syndrome and insulin resistance: a three-armed randomized controlled trial. Hum Reprod. 2022;37:542–52.
3 Huang S, Hu M, Ng EHY, et al. A multicenter randomized trial of personalized acupuncture, fixed acupuncture, letrozole, and placebo letrozole on live birth in infertile women with polycystic ovary syndrome. Trials. 2020;21:239.
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