This pilot randomized, placebo-controlled trial showed that for patients with IBS-D, mild moxibustion had a 44.74–percentage point higher response rate at week 6 and a 50.02–percentage point higher at week 12 than placebo moxibustion group. This means mild moxibustion not only provided short-term relief but also long-term relief persisted up to 12 weeks after treatment. Patients in the mild moxibustion group also had improvements in IBS-SSS total score and each domain up to follow-up visit (12-week). Meanwhile, the quality of life had improved in the mild moxibustion group at week 6. In addition, there were no severe AEs during the entire study.
To the best of our knowledge, no prior RCT has evaluated the effect of different moxibustion on IBS-D. The findings of our previous trial that investigated the effects for IBS-D, showed the moxibustion is a promising therapy[25, 26]. And mild moxibustion could significantly improve some of the most intrusive symptoms of IBS patients. Results of systematic reviews of the literature indicate that moxibustion may be a beneficial therapy in relieving IBS symptoms, but this conclusion was based on studies that were at high risk of bias in the included studies[13, 15, 27]. A great number of studies have shown that acupuncture or acupuncture combined with mild moxibustion has a certain effect on IBS-D[12, 28]. This trial is the first study focus on the different methods of moxibustion for IBS-D in short- and long-term improvement of response rates, IBS-SSS, and IBS-QOL.
Many studies have demonstrated the efficacy of moxibustion in treating IBS-D, but It still remains unclear how moxibustion alleviates IBS-D. Our previous studies indicate that moxibustion could affect intestinal microbes[30, 31], visceral hypersensitivity[31, 32], the brain-gut axis[14, 16], gastrointestinal function. Other studies showed the moxibustion or acupuncture have benefit effect for IBS-D by regulating the neuroendocrine system, the immune system, and other factors.
Our study also has several limitations. First, the blinded were not completely assessed. Compared with the placebo group, the mild moxibustion group was difficult to exclude the placebo effect due to the obvious warm feeling. In the future, the placebo moxibustion group should try to eliminate the influence of temperature, but at the same time ensure that it does not stimulate the acupoints. This will blind the patients and minimize the placebo effect. Second, the time of visits was few. We only assessed the response rates at week 6 and week 12, it was impossible to accurately assessed when moxibustion works and the long-term effect during the follow-up period. Further research should set multiple visit time points and measure longer-term outcomes for different moxibustion. Third, we only assess the efficacy of mild moxibustion for IBS-D, the effect of mild moxibustion was satisfactory for IBS-D, not for IBS-C. Therefore, we could not determine the IBS-C that can benefit more from mild moxibustion. Finally, we only assessed the effect of mild moxibustion for IBS-D, in future studies we could use 3 or more methods of moxibustion to investigate the optimal method of moxibustion for IBS-D.