Effectiveness Of Probiotics In Irritable Bowel Syndrome: A Systematic Review With Meta-Analysis.

Abstract

AIM: To investigate the efficacy of probiotics in irritable bowel syndrome (IBS) patients. METHODS: PubMed, Cochrane library, Scopus, Google Scholar, and Clinicaltrial.gov databases were searched for literature published between September 2007 and December 2013. The applied Mesh terms were “probiotics,” “irritable bowel syndrome,” and “irritable bowel syndrome treatment.” The collected data contained24 clinical trials, of which 15 were eligible for meta-analysis and nine were reviewed systematically. All studies were randomized placebo-controlled trials in patients with IBS that investigated the efficacy of probiotics in IBS improvement. The Jadad score was used to assess the methodological quality of trials. The quality scale ranges from 0 to 5 points, with a score ≤ 2 indicating a low quality report, and a score of ≥ 3 indicating a high quality report. Relative risk (RR), standardized effect size, and 95%CI were calculated using the DerSimonian-Laird method. The Cochran Q test was used to test heterogeneity with P < 0.05. Funnel plots were constructed and Egger’s and BeggMazumdar tests were performed to assess publication bias. RESULTS: A total of 1793 patients were included in the meta-analysis. The RR of responders to therapies based on abdominal pain score in IBS patients for two included trials comparing probiotics to placebo was 1.96 (95%CI: 1.14-3.36; P = 0.01). RR of responders to therapies based on a global symptom score in IBS patients for two included trials comparing probiotics with placebo was 2.43 (95%CI: 1.13-5.21; P = 0.02). For adequate improvement of general symptoms in IBS patients, the RR of seven included trials (six studies) comparing probiotics with placebo was 2.14 (95%CI: 1.08-4.26; P = 0.03). Distension, bloating, and flatulence were evaluated using an IBS severity scoring system in three trials (two studies) to compare the effect of probiotic therapy in IBS patients with placebo, the standardized effect size of mean differences for probiotics therapy was -2.57 (95%CI: -13.05--7.92). CONCLUSION: Probiotics reduce pain and symptom severity scores. The results demonstrate the beneficial effects of probiotics in IBS patients in comparison with META-ANALYSIS Submit a Manuscript: http://www.wjgnet.com/esps/ Help Desk: http://www.wjgnet.com/esps/helpdesk.aspx DOI: 10.3748/wjg.v21.i10.3072 World J Gastroenterol 2015 March 14; 21(10): 3072-3084 ISSN 1007-9327 (print) ISSN 2219-2840 (online) © 2015 Baishideng Publishing Group Inc. All rights reserved. 3072 March 14, 2015|Volume 21|Issue 10| WJG|www.wjgnet.com inhibitors, tricyclic antidepressants, and 5-hydroxytryptamine type-3 antagonists such as ramosetron and alosetron, and lubiprostone and linaclotide. However, due to lack of favorable efficacy and associated adverse events with pharmacologic treatments, some IBS patients look for alternative treatments such as herbal medications and Chinese acupuncture. Probiotics are live microorganisms which have been demonstrated to exhibit potential effects on human health. Probiotics may influence the IBS symptoms including abdominal pain, bloating, distension, flatulence, altered bowel movements, and gut microbiota. The nature of probiotics explains their beneficial role in intestinal function as they can protect against pathogenic bacteria via their antimicrobial properties. Probiotics also amplify the intestinal tight junctions and stabilize the permeability. Moreover, probiotics stimulate goblet cells to produce mucus to enhance the intestinal barrier function, normalize bowel movements, and reduce visceral hypersensitivity in pediatric and adult patients. Several probiotic strains showed beneficial outcomes in IBS patients. The present study was performed to update the previous meta-analysis with consideration of further clinical trials. A systematic review has been also conducted to assess the efficacy of probiotics in IBS patients in clinical trials that were not eligible for inclusion in the meta-analysis. MATERIALS AND METHODS Data sources PubMed, Cochrane library, Scopus, Google Scholar, and Clinicaltrial.gov databases were searched for articles published between September 2007 and December 2013. The applied Mesh terms were “probiotics,” “irritable bowel syndrome,” and “irritable bowel syndrome treatment.” Study selection Three reviewers inspected the topic and abstracts of all articles to eliminate identical studies, review articles, systematic reviews, and meta-analysis investigations. All relevant characteristics of included trials, such as IBS type, probiotic strain, dose of probiotics, trial and follow-up duration, and patient characteristics and outcomes, were collected and summarized. All randomized controlled trials that considered IBS symptom improvement as outcome of interest were included. The reference lists of searched articles were reviewed to identify any additional eligible articles. Assessment of trial quality The Jadad score, which indicates the quality of studies based on their description of randomization, blinding, and dropouts (withdrawals), was used to assess the methodological quality of trials. The quality Didari T et al . Effectiveness of probiotics in IBS 3073 March 14, 2015|Volume 21|Issue 10| WJG|www.wjgnet.com placebo.