Study design
ATIBS-D was a parallel three-group, multicenter randomized trial with 2-week screening, 4-week treatment, and 8-week follow-up for patients with IBS-D. The study protocol has been published on Trials (see Additional file 1). We recruited patients from 4 tertiary hospitals in North and Southwest China, March 2020 to December 2020, and fourteen-week data collection completed in March 2021. Recruitment strategies included posting recruitment advertisements on social media (such as WeChat, which is similar to Facebook) and at hospital clinics (such as flyers in physician offices and posters in the public area of hospitals). This study was approved by the Ethics Committee of the coordinating center (see Material 1 and 2 of Additional file 2) and each study site, and informed consent were provided for all participants before randomization. The study was registered in Chinese Clinical Trial Registry under the number ChiCTR2000030670.
Participants
Rome IV criteria for IBS-D was main criteria for eligibility assessment, participants were eligible if they fulfilled following criteria at 2-week screening, defined as: (I) Patients of IBS-D aged between 18 and 75 years (either sex); (II) Type 6 or 7 of the Bristol Stool Form Scale appeared for at least 4 days and type 1 or 2 appeared for less than 4 days in last 2 weeks; (III) The average score of daily abdominal pain was ≥ 3 in the last week.
Exclusion criteria: (I) Patients with the following diseases: inflammatory bowel disease, microscopic colitis, celiac disease, Crohn's disease and other organic bowel diseases (age ≥ 50 years or have the following alarm signs will be required to provide colonoscopy report within nearly 2 years: unexplained weight loss [weight loss > 10% within 3 months]; hematochezia caused by non-hemorrhoids or anal fissure; nocturnal diarrhea; family history of colorectal cancer); diabetes mellitus and abnormal thyroid function; severe acute or chronic organic diseases, kidney or liver diseases; (II) History of previous abdominal surgery (appendectomy, hemorrhoidectomy, or polypectomy greater than 3 months post-surgery are allowed.); (III) Pregnancy or lactation, or history of alcohol and drug abuse; (IV) Treated with acupuncture in the last 6 months, or participating in other clinical trials; (V) Usage of antidepressant or IBS medication within 2 weeks before treatment, including Traditional Chinese Medicine (TCM) or proprietary Chinese medicine, antidiarrheal, antispasmodic, intestinal antibiotics, probiotics and so on.
Randomization And Blinding
After completing baseline questionnaires, participants were randomized to one of the three trial arms (SA group, NSA group and NA group) according to the ratio of 1:1:1. Randomization was stratified by recruitment site, with fixed block size of 6. An independent statistician who was not involved in the implementation or statistical analysis of this trial generated the blocked randomization sequence by using the software SAS 9.3. As with any therapy trial, acupuncturists and her/his assistants could not be masked to treatment allocation. Participants, clinical recruiters, outcome assessors, data managers, and statisticians were blinded.
Study Procedures
All researchers in different divisions of labor have undergone rigorous training to standardized procedures of trial. They also received researcher manuals to remind them of inclusion criteria, details of assessment and treatment and so on. Participants recorded defecation diary (see Figure 1 of Additional file 2) throughout the trial. Before receiving the first treatment, all participants received baseline assessments, including assessments of IBS-D related symptoms via defecation diary of 2-week screening, IBS Symptom Severity Scale (IBS-SSS), and IBS-Quality of Life scale (IBS-QoL) [17, 18]. For IBS-SSS, a decrease of 50 points is adequate to reliably indicate clinical improvement [17]. For IBS-QoL, higher scores indicate better QoL, and a meaningful clinical response is represented by an increase of at least 14 points [19]. Anxiety and depression were assessed via Patient Health Questionnaire-9 depression scale (PHQ-9) [20]. After the first treatment, patients were asked to complete the credibility and expectancy questionnaire in 5 minutes [21]. During the 4-week treatment and 8-week posttreatment follow-up, we completed comprehensive assessments of patients by IBS-SSS, IBS-QoL, PHQ-9, IBS Adequate Relief (IBS-AR) and related IBS-D individual symptoms (abdominal pain, bloating, loose stool day and stool frequency) [22]. To test the implementation of blinding, patients were asked to guess which kind of acupuncture they received after the last treatment. Adverse events and usage of rescue medicine were monitored and recorded at assessment time points during the treatment and follow-up phases of trial.
Interventions
Participants received 12 sessions (3 sessions per week) of 30-minute treatment overall 4-week treatment phase. Single-use sterile needles (length: 25 to 40 mm; diameter: 0.30 mm; Hwatuo, Suzhou, China) were used in SA group and NSA group. Blunt-tipped placebo needles (similar to the Streitberger design) with a similar appearance to conventional needles but no skin penetration, were used in NA group [23, 24]. Adhesive pads were placed on puncture points in all groups which is to help maximize blinding of participants in NA group and to fix blunt-tipped placebo needles. The treatments were administered by certified acupuncturists who had 5 years of undergraduate education on acupuncture and at least 3 years of clinical experience. Each acupuncturists received a 2-day training who could perform treatments of all group, with priority given to the same acupuncturist delivering treatment to a specific participant throughout the trial whenever possible.
Participants in SA group received acupuncture at 6 acupoints (5 fixed acupoints and one of 3 optional acupoints) according to the syndrome diagnosis and the principle of matching specific points for He-acupoint and Mu-acupoint. The six fixed acupoints of NSA group were chose based on the usage frequency of acupoints. Insertion was followed by stimulation performed by lifting and thrusting the needle combined with twirling and rotating the needle sheath to produce the sensation known as deqi (sensation of soreness, numbness, distention, or radiating, which is considered to indicate effective needling) [25]. Five non-acupoints which away from meridians or conventional acupoints were selected in NA group without manipulations. The location of acupoints in each group was described in our study protocol [26].
Outcomes
For primary endpoint, a composite response rate at week 4 of treatment phase were used in accordance with FDA recommendations. An eligible composite responder was responded in both abdominal pain intensity and stool consistency, defined as at least a 30% decrease in the weekly average of worst abdominal pain in the past 24 hours score compared with baseline and a 50 percent or greater reduction in the number of days per week with at least one stool that has a consistency of Type 6 or 7 compared with baseline. For secondary endpoints, IBS-SSS, IBS-QoL, and PHQ-9 were assessed at weeks 2, 4, 8 and 12, and the response rates at other time points (without week 4), IBS-AR, and IBS-D individual symptoms were assessed at weeks 1, 2, 3, 4, 8 and 12 after randomization. Regard to individual symptoms of IBS-D, abdominal pain and bloating were assessed by 0-10 numerical rating scale (NRS), and Bristol stool score (BBS) were used to record loose stool day and stool frequency of participants.
Statistical analysis
This exploratory study aimed to assess the efficacy of SA, NSA, and NA for IBS and determine the feasibility of a further large-scale clinical trial. According to Provisions for Drug Registration in China, the minimum sample size for exploratory trials is 20-30 per group, and 90 participants (30 patients for each group) were randomized eventually. Intention-to-treat (ITT) set was used in all efficacy analysis, which consisted of all patients who had been randomized, and the missing data was imputed using last observation carried forward (LOCF). Relevant data were summarized with counts and percentages for categorical data, whereas with mean ± standard deviation (M ± SD) for continuous data.
The differences among the three groups in primary endpoint (composite response rate at week 4) were analyzed using the χ² test. Additionally, a logistic generalized linear mixed model included baseline abdominal pain score and stool consistency as covariates was used, with time, and group as fixed factors; patient as a random factor; and logit function set as the link function. A per-protocol analysis was used for primary outcome as sensitivity analysis covering patients who complete ≥10 sessions and have no major protocol violations (taking other drugs during the trial, etc.) [25].
For change scores of IBS-SSS, IBS-QoL, PHQ-9 and IBS-D individual symptoms (abdominal pain, abdominal bloating, loose stool days, and stool frequency), the Analysis of Variance (ANOVA) was used for comparison among the three groups. The response rates at other time points, IBS-AR, blinding assessment, the credibility and expectancy, and adverse event rates were analyzed using the χ² test or Fisher’s exact test. We concentrated on the overall comparison among three groups, and provided comparative descriptions for the results of pairwise comparisons merely. All reported P values are two-sided with a significance level less than 0.05.