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Impact of Clinical Outcome Measures on Placebo Response Rates in Clinical Trials for Chronic Constipation: A Systematic Review and Meta-analysis.
Chen, J, Liu, X, Bai, T, Hou, X
Clinical and translational gastroenterology. 2020;(11):e00255
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Abstract
OBJECTIVES Chronic constipation (CC) is a recurrent functional bowel disorder worldwide. The purpose of this study is to examine its pooled placebo response rate and compare placebo response level in randomized controlled trials (RCTs) with different endpoint assessments. METHODS PubMed, Cochrane Library, and Embase were electronically searched for therapeutic RCTs of CC with placebo control. Data extraction and assessment of risk of bias were performed independently by 2 reviewers. All the statistical calculation and analysis were performed using R 3.6.0. Our protocol has registered in PROSPERO with registration number: CRD42019121287. RESULTS There were 46 studies included with 5,992 constipated patients allocated to the placebo arm in total. The pooled placebo response rate was 28.75% (95% confidence interval: 23.83%-33.67%) with significant heterogeneity among trials ((Equation is included in full-text article.)= 93.6%). Treatment efficacy assessed using subjective improvement had a significantly higher placebo response rate than that assessed with improvement in complete (spontaneous) bowel movements or composite improvement (41.40% vs 18.31% or 20.35%, P < 0.001). According to the results of meta-regression, active treatment and endpoint assessment were most likely to lead to the huge heterogeneity among studies. DISCUSSION Patients with CC have significant response level to placebo. Based on findings in this study, we do not recommend subjective improvement as endpoint while designing therapeutic RCTs for chronic constipated patients.
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Effectiveness and safety of light vegetarian diet and Qingjiang Tiaochang Recipe for functional constipation: An exploratory study protocol for randomized controlled trial.
Liu, X, Liu, Y, Chen, J, Wang, H, Wang, Q, Niu, Z, Yun, Z, Ma, B, Yao, S
Medicine. 2020;(39):e21363
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Abstract
INTRODUCTION Functional constipation is a chronic disease that is common in children and adults around the world. The treatments for functional constipation include diet and lifestyle interventions, medications, and surgery. The diet pattern plays an important role in the occurrence of constipation. We found in clinical practice that simple application of drugs cannot achieve long-term relief of constipation, and a large number of patients are not satisfied with the existing treatment. We have concluded that Qingjiang Tiaochang Recipe (QJTCR) and light vegetarian diet (LVD) can effectively improve constipation. However, there is no enough evidence for the description of the effect. This protocol aims at exploratorily investigating effectiveness and safety of LVD and QJTCR following a rigorous clinical trial. METHODS AND ANALYSIS We will recruit 90 patients to participate in this prospective, placebo-controlled, randomized trial, and exploratory study at the China-Japan Friendship Hospital, including traditional Chinese medicine group, placebo + diet group, traditional Chinese medicine + diet group. Patients in the diet intervention group must strictly abide by LVD, and the study will continue for 28 days. During the intervention period, we need to record a designed diary to assess diet quality and defecation. The primary outcomes for this clinical study were weekly complete spontaneous bowel movements. The secondary outcomes were constipation-related symptom rating scale, traditional Chinese medicine syndrome scale, and 48-hour gastrointestinal transit time, high-resolution anorectal manometry, Bristol stool score, constipation quality of life assessment scale, constipation symptoms self-assessment scale, short-chain fatty acids in feces. In addition, the study will determine the safety of the intervention.