Abstract
OBJECTIVES: This study aimed to pool the efficacy in bowel movement and explore the change of gut microbiota on adult functional constipated patients after probiotics-containing products treatment. DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed, Cochrane Library for published studies and ClinicalTrials.gov for 'grey' researches were independently investigated for randomised controlled trials up to November 2022. ELIGIBILITY CRITERIA, DATA EXTRACTION AND SYNTHESIS: The intervention was probiotics-containing product, either probiotics or synbiotics, while the control was placebo. The risk of bias was conducted. The efficacy in bowel movement was indicated by stool frequency, stool consistency and Patient Assessment of Constipation Symptom (PAC-SYM), while the change of gut microbiota was reviewed through α diversity, β diversity, change/difference in relative abundance and so on. The subgroup analysis, sensitivity analysis and random-effect meta-regression were conducted to explore the heterogeneity. The Grading of Recommendations Assessment Development and Evaluation was conducted to grade the quality of evidence. RESULTS: 17 studies, comprising 1256 participants, were included with perfect agreements between two researchers (kappa statistic=0.797). Compared with placebo, probiotics-containing products significantly increased the stool frequency (weighted mean difference, WMD 0.93, 95% CI 0.47 to 1.40, p=0.000, I(²)=84.5%, 'low'), improved the stool consistency (WMD 0.38, 95% CI 0.05 to 0.70, p=0.023, I²=81.6%, 'very low') and reduced the PAC-SYM (WMD -0.28, 95% CI: -0.45 to -0.11, p=0.001, I²=55.7%, 'very low'). In subgroup analysis, synbiotics was superior to probiotics to increase stool frequency. Probiotics-containing products might not affect α or β diversity, but would increase the relative abundance of specific strain. CONCLUSIONS: Probiotics-containing products, significantly increased stool frequency, improved stool consistency, and alleviated functional constipation symptoms. They increased the relative abundance of specific strain. More high-quality head-to-head randomised controlled trials are needed.