Stimulated by Gao et al 2026.[1]
EA – electroacupuncture
MA – manual acupuncture
USCC – ultra severe chronic constipation
SCC – severe chronic constipation
CACMS – China Academy of Chinese Medical Sciences
IF – impact factor
CSBM – complete spontaneous bowel movement
MCID – minimal clinically important difference
OIC – opioid-induced constipation– key to acronyms
This is a secondary analysis of a large non-inferiority trial I highlighted here back in January 2021, see EA vs Prucalopride in SCC.[2] It is now the fourth post in the constipation category, and all the highlighted trials come from the same team from CACMS, based in Beijing.
The team has published several large acupuncture trials in prominent journals, and they have gone on to perform secondary analyses like this one, which often get published in more specialist journals with lower IF.
The subgroup reanalysed in this case were simply a more severely affected group – USCC rather than SCC. The definitions are based on the CSBMs, and to get into the original trial the patients needed to have no more than 2 per week, whereas for this analysis, only those patients with no CSBMs per week were included.
The original trial included 560 patients, and of these 317 met the definition of USCC and were included in the secondary analysis. When you start with such a large trial there are more options for secondary analyses that may achieve the required statistical power. The original trial was powered with reference to the effect of prucalopride over placebo. With hindsight it looks as if it was over-powered, since there was no difference between the groups in the intermediate to long term, and EA clearly met the standard for non-inferiority.
In the short term, the drug appears to reach optimal effects by the end of the first week, whereas EA takes 2 to 6 weeks to reach the same level of effect.
I learned from this paper that the MCID for CSBMs is 1.3, although the references supporting that were not accessible. If this had been used as the margin for non-inferiority or even equivalence, then the two interventions would clearly have been equivalent.
The acupuncture was quite an intense treatment course, with 28 sessions of EA in 8 weeks, starting with 10 in the first 2 weeks. Follow the link to the previous blog to see the details.
The first trial to use this protocol was the biggest sham controlled trial of EA (and indeed any acupuncture technique) to date, with a total of 1075 patients distributed over just 2 arms.[3] It was discussed on this blog in 2018, see EA for chronic severe functional constipation. EA produced a clinically relevant improvement in CSBMs and a significantly better effect than sham EA.
Following this trial there were 3 secondary publications. The first examined the initial response to EA and found that this correlated with a younger age and higher number of baseline CSBMs.[4] The second paper studied the duration of EA effects, which was the time individuals maintained responder status (defined as 3 or more CSBMs per week).[5] Again, this correlated with a younger age and higher number of baseline CSBMs. Finally, the third spin-off paper was focussed on the effect in women.[6] 822 of the 1075 in the original trial were women, and their results matched the original trial.
The only other trial from this group that I have not mentioned here yet is the one focussed on constipation related to the use of opioid medication in cancer patients (n=100).[7] This was a smaller sham controlled trial and I featured it on the blog in February 2023, see EA for OIC.
References
1 Gao S, Zhu L, Yao H, et al. Effect of electroacupuncture versus prucalopride for ultra-severe chronic constipation: Secondary analysis of a randomized controlled trial. Integr Med Res. 2026;15:101253. doi: 10.1016/j.imr.2025.101253
2 Liu B, Wu J, Yan S, et al. Electroacupuncture vs Prucalopride for Severe Chronic Constipation: A Multicenter, Randomized, Controlled, Noninferiority Trial. Am J Gastroenterol. 2021;116:1024–35. doi: 10.14309/ajg.0000000000001050
3 Liu Z, Yan S, Wu J, et al. Acupuncture for Chronic Severe Functional Constipation: A Randomized Trial. Ann Intern Med. 2016;165:761–9. doi: 10.7326/M15-3118
4 Zeng Y, Liu Y, Liu S, et al. Initial Effects of Electroacupuncture for Chronic Severe Functional Constipation and the Potential Underlying Factors: Secondary Analysis of a Randomized Controlled Trial. Evid-Based Complement Altern Med ECAM. 2019;2019:7457219. doi: 10.1155/2019/7457219
5 Wang Y, Liu Y, Zhou K, et al. The duration of acupuncture effects and its associated factors in chronic severe functional constipation: secondary analysis of a randomized controlled trial. Ther Adv Gastroenterol. 2019;12:1756284819881859. doi: 10.1177/1756284819881859
6 Zhou J, Liu Y, Zhou K, et al. Electroacupuncture for Women with Chronic Severe Functional Constipation: Subgroup Analysis of a Randomized Controlled Trial. BioMed Res Int. 2019;2019:7491281. doi: 10.1155/2019/7491281
7 Wang W, Liu Y, Yang X, et al. Effects of Electroacupuncture for Opioid-Induced Constipation in Patients With Cancer in China: A Randomized Clinical Trial. JAMA Netw Open. 2023;6:e230310. doi: 10.1001/jamanetworkopen.2023.0310
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