Randomised clinical trial: a liquid multi-strain probiotic vs. placebo in the irritable bowel syndrome - a 12 week double-blind study

Background The importance of interactions between the host and gut microbiota in the pathogenesis of irritable bowel syndrome (IBS) is becoming increasingly apparent. Probiotics offer a potential new treatment for IBS, but current results are conflicting, largely as a result of poorly designed trials and nonstandardisation of outcome measures. Aim To assess the efficacy of a liquid, multi-strain probiotic (Symprove) in IBS. Methods A single-centre, randomised, double-blind, placebo-controlled trial of adult patients with symptomatic IBS. Patients received 12 weeks of treatment with the probiotic or placebo (1 mL/kg/day). The primary efficacy measure was the difference in change in the IBS symptom severity score (IBS-SSS) between probiotic vs. placebo at week 12. Secondary outcome measures included change in the IBS quality of life (IBS-QOL) score and change in the IBS-SSS symptom component scores. Results A total of 186 patients were randomised and 152 patients completed the study. The mean change in IBS-SSS was -63.3 probiotic vs. -28.3 placebo. The mean difference in the IBS-SSS was statistically significant [-35.0 (95% CI; -62.03, -7.87); P = 0.01]. There was no significant improvement in the IBS-QOL. No serious adverse events were reported. Conclusions The multi-strain probiotic was associated with a statistically significant improvement in overall symptom severity in patients with IBS, and was well tolerated. These results suggest this probiotic confers benefit in IBS and deserves further investigation (ISRCTN identifier: 77512412).