The protocol for this trial is reported based on the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 Checklist: defining standard protocol items for clinical trials (Additional file 1). The study has been approved by the Ethics Committee of Jiangsu Province Hospital of TCM (the Approved No. of the Ethics Committee is 2015NL-030-02) and was registered on at the Chinese Clinical Trial Registry (Chictr) platform on 14 April 2015 (Registration number: ChiCTR-IOR-15006259).
Study design
This study is a multicenter, stratified randomized controlled trial (RCT), comparing acupuncture to standard pharmacological treatment for two subtypes of IBS: IBS-C (constipation-predominant IBS) and IBS-D (diarrhea-predominant IBS). The study is being conducted in the following seven hospitals: Jiangsu Hospital of TCM, Wuxi Hospital of TCM, Nantong Hospital of TCM, Nanjing Hospital of Chinese Medicine, Zhenjiang Riverside Hospital, Kunshan Hospital of TCM, and Shuyang Hospital of TCM. The study will be carried out according to the principles of the Declaration of Helsinki (version Edinburgh 2000).
This study will be performed over a period of 19 weeks: 1 week of wash-out, 6 weeks of treatment, and 12 weeks of post-treatment follow-up. All eligible patients will be stratified into two strata: IBS-C or IBS-D. The patients within each stratum will then randomly divided to either an acupuncture group or a control group receiving standard pharmacological treatment. Outcomes will be assessed at baseline, during the treatment and at the end of the follow-up. Figures 1 and 2 illustrate the time schedule of enrollment, interventions, assessments, and participant visits.
Randomization and blinding
The Good Clinical Practice (GCP) Center of Jiangsu Province Hospital of TCM will be responsible for generating the randomization sequence. All eligible participants will be told not to take any treatment for IBS for 1 week (the wash-out period). After the wash-out period, all the participants will be stratified into IBS-C or IBS-D subgroups and then randomly allocated to either the acupuncture group or the control group by a central randomization system. An allocation ratio of 2:1 will be used in the acupuncture to control group assignment. Only the outcome assessors and the statisticians will be blinded to the allocation. The outcome assessors and the statisticians will not participant in the treatment, they will perform the outcome evaluation and the statistical analysis independently.
Study participants and the recruitment
Participants will be recruited from the outpatient centers of the seven participating hospitals and their surrounding communities by posting and distributing posters and flyers about this trial.
The following inclusion criteria will be used: (1) adults aged 18–70 years, (2) diagnosis of IBS-C or IBS-D, as defined by ROME III diagnostic criteria [4], (3) IBS duration of 6 months or longer, (4) lack of morphological changes and biochemical abnormalities that could explain the symptoms, (5) baseline IBS-Symptom Severity Score (IBS-SSS) score of 75 points or greater, (6) no acupuncture treatment for 3 months preceding the trial, (7) no participation in any other ongoing clinical trial, and (8) agreement to participate and signing of the informed consent document.
The exclusion criteria are: (1) diagnosis of an organic intestinal disease, (2) history of abdominal and/or rectal surgery, (3) history of drug dependence for gastrointestinal motility and function, (4) other serious medical conditions, such as cardiovascular disease, endocrine disorders, hepatic dysfunction, cerebral vascular disease, renal diseases, and cognitive disorders, and (5) pregnancy, lactation, and postpartum period of less than 12 months. Physical examination will be conducted at the time of recruitment to exclude participants with serious diseases not suitable for this trial.
Acupuncture and the control group
Patients in the acupuncture group, regardless of the IBS subtypes, will receive acupuncture three times a week for 6 weeks for a total of 18 treatment sessions. Patients will receive treatment in supine position for 30 min per session. The treatment will be provided by licensed acupuncturists holding acupuncture physician certifications in China with at least 2 years of clinical experience. Disposable, sterile needles with a diameter of 0.30 mm and a body length of 40 mm (Huatuo, Suzhou, China) will be used. Based on TCM theory and our clinical experience, acupoints used here are unilateral GV20 (Bai Hui), GV29 (Yin Tang) and bilateral LR3 (Tai Chong), ST36 (Zu San Li), SP6 (San Yin Jiao), ST25 (Tian Shu), and ST37 (Shang JuXu) (Fig. 3). The exact location and depth of needling for each point will be determined based on the 2006 People’s Republic of China National Standard (GB/T 12346–2006) Acu-Points Name and Location [23]. After insertion, all points will be manually stimulated by lifting and thrusting the needle every 10 min to elicit the “deqi” and the needles will be retained for 30 min.
The patients in the control group will receive standard pharmacological treatment based on the IBS subtype. Patients with IBS-C will take macrogol 4000 powders (Fu Song, two bags per day, dissolved in a glass of water before taking) for 6 weeks. Patients with IBS-D will take pinaverium bromide tablets (Dicetel, 50 mg tid, swallowing pills with water during meals without breaking, chewing or dissolving) for 6 weeks.
Outcome assessment
The primary outcome measure of this trial is the IBS-Symptom Severity Score (IBS-SSS), a validated scoring system for assessing the severity of IBS [24, 25]. The questionnaire is scored from 0 to 500 and is composed of five 100-point scales that measure the severity of pain, duration of pain, severity of abdominal distention, dissatisfaction with bowel habits, and disruption in life quality. The scores are classified into no IBS (< 75), mild IBS case (75–175), moderate IBS case (175–300), and severe IBS case (> 300) [25]. IBS-SSS is assessed at baseline, 1, 2, 4, 6, and 18 weeks.
The secondary outcome measures include the IBS-Quality of Life (IBS-QoL) and genotyping of the patients’ serotonin-related genes. The IBS-QoL is a 34-item questionnaire for determining the degree to which IBS interferes with the patient’s quality of life [26]. It is composed of eight dimensions, including dysphoria, interference with activity, body image, health worry, food avoidance, social reaction, sex, and relationships. Each item is evaluated on a 5-point rank scale with a higher score indicating a better quality of life. The IBS-QoL will be measured at baseline and 6 and 18 weeks.
DNA isolation and genotyping will be performed to study the possible correlation between the therapeutic effectiveness of acupuncture and the following polymorphisms of serotonin-related genes: (1) HTTLPR (L/L, L/S, S/S), (2) STin2 VNTR (STin2 12/12, STin2 12/10, STin2 12/9, STin2 10/10, STin2 9/9), and (3) rs25531 (rs25531-G). The patients’ blood samples will be collected at the baseline. The correlation between IBS-gene subtypes and acupuncture effect will be detected based on cleaved amplification polymorphism sequence-tagged sites.
Safety evaluation
During the study, adverse events (AEs) are defined as any unexpected or undesired harmful effect resulting from acupuncture or pharmacological treatment. A research assistant (GL) will be required to record all the AEs, including information on the time of occurrence, severity, duration, measurement, management, and its outcome, in a case report form (CRF). Any serious adverse events (SAEs) will be immediately reported to the principal investigator (JHS) and the Medical Ethics Committee within 24 h. The Acupuncture Department of Jiangsu Province Hospital of TCM will be responsible for the treatment of all the AEs.
Sample size calculation and statistical analysis
Based on our previous clinical experience and the previous literature, we anticipate an improvement of 115 points in the acupuncture group and 105 points in the control group on the IBS-SSS. The standard deviation is set at 37, and the ratio between the acupuncture and control groups is 2:1. The sample size is calculated with 80% power and 5% type I error using G*Power software (version, Franz Faul, Universitat Kiel, Germany). This resulted in a required sample size of 322 participants in the acupuncture group and 161 participants in the control group. After accounting for a 20% drop-out rate, 400 participants in the acupuncture group and 200 participants in the control will be included.
Statistical analysis of all data in this study will be performed by a specialized statistician, who is blinded to the treatment allocation. Statistical Package for the Social Sciences (SPSS) V.24.0 (SPSS Inc., Chicago, IL, USA) will be used for data analysis. All analysis will be on the basis of the intention-to-treat (ITT) population and the per-protocol (PP) population. ITT requires all participants in a clinical trial to be included in the analysis in the groups to which they were randomized, regardless of any departures from randomized treatment. The PP population is usually defined as all patients completing the study without major protocol deviations – that is those who followed the rules of the study. The results of each population will be compared for stabilization. Last-observation-carried-forward will be used in the case of missing data. The principal investigator will take responsibility for the results of the data analysis. In terms of data description, quantitative and qualitative data will be presented as mean ± standard deviation, frequency, percentages or constituent ratios, respectively. Other covariates such as age, gender, ethnicity, disease duration, marital status, educational level, weight (in kilograms), and height (in meters) will be considered for further revision. In case of normality of distribution and homoscedasticity, the baseline characteristics will be performed using the analysis of covariance (ANCOVA) model, and the multiple comparisons will be performed with the Least Significant Difference test. In addition, a repeated- measure analysis of variance (rm-ANOVA) will be used to determine, within each group, the difference between baseline and 1, 2, 4, 6, and 18 weeks for both the IBS-SSS and the IBS-QoL. On this occasion of non-normal distribution data and heteroscedasticity data, the non-parametric Kruskal-Wallis test will be performed, and the Nemenyi test will be done to identify the difference between the groups. Pearson’s chi-squared test will be used in the transformed categorical data. Lastly, we will conduct rm-ANOVA to analyze genotype-related effects on treatment response. The Huynh-Feldt correction will be used if the assumption of sphericity is violated. A two-sided p value of less than 0.05 will be considered statistically significant for all analyses.
Data management and monitoring
All the researchers will focus on and sign to protect the individual privacy of the participants. The raw data will be collected and cross-checked by two researchers (WLX and SQ). The database software EpiData (version 3.1) will be used for the data management. All the management will be performed in compliance with the study Standard Operation Process (SOP).
The Department of Science and Technology in Jiangsu Province Hospital of TCM, which is not taking part in the study, will be responsible for the monitoring. The CRFs, protocol compliance, data management, treatment administration and AEs will be monitored independently during the study.