Abstract
- Objective
Previous systematic reviews demonstrated a potentially beneficial effect of probiotics on irritable bowel syndrome. However, these studies are either affected by the inclusion of insufficient trials or by the problem of dependent data across multiple outcomes, and an overall effect size has not been provided. We aimed to determine the effect of probiotics on irritable bowel syndrome through a three-level meta-analysis and clarify potential effect moderators.
- Methods
We searched MEDLINE, Embase, and Web of Science, screening for randomized controlled trials examining the effect of probiotics on irritable bowel syndrome. The primary outcome was the improvement in the severity of global irritable bowel syndrome symptoms at the end of treatment. Secondary outcomes included the improvement in abdominal pain and quality of life. Effect sizes were measured using the standardized mean difference and pooled using a three-level meta-analysis model.
- Results
Seventy-two randomized controlled trials were included in the analysis. The meta-analysis showed a significantly better overall effect of probiotics compared to placebo on global irritable bowel syndrome symptoms (standardized mean difference: −0.55; 95% confidence interval: −0.76 to −0.34; $P < 0.001$), abdominal pain (standardized mean difference: −0.89; 95% confidence interval: −1.29 to −0.5; $P < 0.001$), and quality of life (standardized mean difference: 0.99; 95% confidence interval: 0.45 to 1.54; $P < 0.001$). Moderator analysis indicated that a treatment duration shorter than four weeks was associated with a larger effect size across all outcomes, and Bacillus probiotics showed superior improvement in abdominal pain.
- Conclusions
Probiotics yield a short-term and medium effect size on global irritable bowel syndrome symptoms. Treatment duration and probiotic types modulate the effect size, where shorter durations and Bacillus probiotics are associated with enhanced therapeutic outcomes.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10651259/