Efficacy and safety of probiotics in irritable bowel syndrome: A systematic review and meta-analysis

Abstract

BackgroundIrritable bowel syndrome (IBS) is a common gastrointestinal disease characterized by abdominal pain, distension, and altered bowel habits. Probiotics may alleviate IBS symptoms, but clinical trials remain conflicting. AimsTo conduct a systematic review and meta-analysis of clinical trials to evaluate the efficacy and safety of probiotics for IBS patients. MethodsWe searched relevant trials in PubMed, Web of Science, Embase, Cochrane Library, and Google Scholar from 2000 to June 2023. Standardized mean difference (SMD) and 95% confidence interval (CI) were calculated for continuous outcomes. A risk ratio (RR) and a 95% CI were calculated for dichotomous outcomes. ResultsA total of 20 studies involving 3011 patients were obtained. The results demonstrated that probiotics are more effective than placebo in reducing global IBS symptoms improvement rate (RR = 1.401, 95% CI 1.182 - 1.662, P < 0.001) and quality of life scores (SMD = 0.286, 95% CI = 0.154 - 0.418, P < 0.001). Subgroup analyses showed that a shorter treatment time (less than eight weeks) could reduce distension scores (SMD = 0.197, 95% CI = 0.038 - 0.356, P = 0.015). High doses (daily dose of probiotics ≥ 10ˆ10) or multiple strains of probiotics exhibit beneficial effects on abdominal pain (SMD = 0.412, 95% CI = 0.112 - 0.711, P = 0.007; SMD = 0.590, 95% CI = 0.050 - 1.129, P = 0.032; respectively). However, there was no significant benefit on global symptom scores (SMD = 0.387, 95% CI 0.122 to 0.653, P = 0.004) with statistically high inter-study heterogeneity (I2 = 91.9%, P < 0.001). Furthermore, there was no significant inter-group difference in terms of adverse events frequency (RR = 0.997, 95% CI 0.845 - 1.177, P = 0.973). ConclusionProbiotics are effective and safe for IBS patients. High doses or multiple probiotic strains seem preferable, but definite conclusions are challenging due to the high heterogeneity. Large-scale, well-designed, and rigorous trials are needed to confirm their effectiveness.