Sijunzi decoction, a classical Chinese herbal formula, improves fatigue symptoms with changes in gut microbiota in chronic fatigue syndrome: A randomized, double-blind, placebo-controlled, multi-center clinical trial

Chronic fatigue syndrome (CFS) severely impact patients' quality of life and lacks well-acknowledged drug therapy. Sijunzi decoction (SJZD), a classical Chinese herbal formula, has been widely used for spleen deficiency syndrome like fatigue in China. However, there is a lack of evidence on the effectiveness of SJZD in treating CFS. To evaluate the efficacy and safety of SJZD for CFS. A multicenter, double-blinded, randomized controlled trial. Participants with definite diagnoses of CFS and spleen deficiency syndrome were randomly assigned in 1:1 ratio to receive SJZD or placebo granules for 2 months. The primary outcome was the change of Chalder fatigue questionnaire (CFQ) scoring after treatment. Other outcomes included changes in short form-36 physical function (SF36-PF) score, spleen deficiency scale score, Euroqol Questionnaire-Visual Analogue Scale (ED-VAS) score, and clinical global impression (CGI) evaluating by corresponding questionnaires. Fecal metagenome sequencing was conducted to explore the potential mechanism of SJZD effect. From June 2020 to July 2021, 105 of 127 participants completed the study at four hospitals in China. After a 2-month treatment, intention-to-treat (ITT) analysis found participants who received SJZD had larger reduction than placebo control (mean change 6.65 [standard deviation (SD) 6.11] points vs. 5.31 [SD 5.19] points; difference 1.34, 95% confidence interval [CI] -0.65 to 3.33). Per-protocol (PP) analysis reported confirmative results with a significant difference between SJZD and placebo group (2.24, 95% CI 0.10 to 4.39). SJZD also significantly improved overall health status compared with placebo in per-protocol population (p = 0.009). No significant difference was found between groups in changes of SF36-PF, spleen deficiency scale scoring, and CGI. Fecal metagenome sequencing and correlation analyses indicated that the beneficial effect of SJZD may be related to the abundance change of Pediococcus acidilactici. No serious adverse event or abnormal laboratory test was found during the whole study. Our results indicated that SJZD can improve fatigue symptom and overall health status in patients with CFS under good medication adherence. Potential therapeutic effects may be related to the regulation of gut microbiota. Large-scale trials with longer intervention period are encouraged to further support SJZD's application. (ID, ISRCTN23930966, URL = https://www.isrctn.com/ISRCTN23930966).