Systematic review and meta-analysis: Efficacy of patented probiotic, VSL#3, in irritable bowel syndrome

Background VSL#3 is a patented probiotic for which several clinical trials suggest benefits on motor function, bloating, and symptoms of irritable bowel syndrome (IBS). Objectives Methods To quantify effects of VSL#3 on abdominal pain, stool consistency, overall response, abdominal bloating, and quality of life (QOL) in IBS through meta-analysis. MEDLINE (OvidSP and PubMed), EMBASE, Web of Science, and Scopus were searched up to May 2017. Using a fixed effects model, we pooled data from intention-to-treat analyses of randomized trials (RCTs) comparing VSL#3 to placebo in IBS. Data were reported as relative risk (RR), overall mean difference (MD), or standardized MD (SMD) with 95% confidence intervals (CI). Quality of evidence was rated using the GRADE approach. Key Results Conclusions & Inferences Among 236 citations, 5 RCTs (243 patients) were included. No significant differences were observed for abdominal pain (SMD = -0.03; 95% CI -0.29 to 0.22), bloating (SMD = -0.15; 95% CI -0.40 to 0.11), proportion of bowel movements with normal consistency (overall MD = 0; 95% CI -0.09 to 0.08), or IBS-QOL (SMD = 0.08; 95% CI -0.22 to 0.39). VSL#3 was associated with a nearly statistically significant increase in overall response (RR = 1.39; 95% CI 0.99-1.98). In this systematic review and meta-analysis, there was a trend toward improvement in overall response with VSL#3, but no clear evidence effectiveness for IBS. However, the number and sample sizes of the trials are small and the overall quality of evidence for 3 of the 5 outcomes was low. Larger trials evaluating validated endpoints in well-defined IBS patients are warranted.