The efficacy and safety of probiotics for patients with constipation-predominant irritable bowel syndrome: A systematic review and meta-analysis based on seventeen randomized controlled trials

Background: & Objectives: Constipation-predominant irritable bowel syndrome (IBS-C) is functional bowel disorders that may involve disturbance of the gastrointestinal microbiota. We performed a systematic review and meta-analysis of the efficacy and safety of probiotics in patients with IBS-C. Methods: We searched the Cochrane Library, PubMed, EMBASE and Web of Science databases up to 1 May 2019. Randomized controlled trials (RCTs) involving adults with IBS-C that compared probiotics to placebo or no therapy were eligible for the analysis. Dichotomous symptom data were pooled to calculate the relative risk (RR) with a 95% confidence interval (CI) of remaining symptoms after therapy. Continuous data were pooled using a standardized or weighted mean difference (MD) with the 95% CI. Two reviewers assessed trial quality and extracted data independently. The analysis was performed using Review Manager version 5.2. Results: Seventeen RCTs involving 1469 patients were included in the analysis. Overall, probiotics significantly increased stool frequency by 1.29 bowel movements (BM)/wk (95% CI: 0.69 to 1.89 BM/wk; P < 0.0001), and improved stool consistency (SMD: 0.55; 95% CI: 0.27 to 0.82; P = 0.0001). Compared with placebo, patients using probiotics experienced a shorter gut transit time by 12.36 h (95% CI: - 20.74 to - 3.98 h; P = 0.004). No serious adverse events were reported. Conclusions: Generally, probiotics may be safe and may improve whole gut transit time, stool frequency, and stool consistency. However, adequately powered RCTs are required to better determine the species or strains, doses, and duration of use of probiotics that are most efficacious. Further research and evidence is required before probiotics is adopted as one of treatments of IBS-C.