Sander Veldhuyzen van Zanten, MD, PhD
Are probiotics effective for treatment of the irritable bowel syndrome (IBS)?
Included studies compared probiotics with placebo or no treatment in adults (> 16 y of age) with IBS and had ≥ 7 days of treatment and follow-up. Outcomes included global IBS symptoms (or abdominal pain if global symptoms not reported), bloating, urgency, and flatus.
MEDLINE and EMBASE/Excerpta Medica (both to Jun 2008) and Cochrane Controlled Trials Register (2007) were searched for randomized controlled trials (RCTs). Conference proceedings from 2001 to 2007 were hand-searched, and bibliographies of included studies were reviewed. 18 RCTs (n = 1650) met the selection criteria. 11 trials were considered high-quality (Jadad scores ≥ 4 out of 5). Probiotics used in trials were Lactobacillus, Bifidobacterium, Streptococcus, or a combination.
Meta-analysis showed that probiotics reduced persistence of IBS symptoms, but there was significant heterogeneity among trials (Table). When analysis was limited to the 5 trials with Jadad scores ≥ 4, the result was no longer significant (relative risk reduction 14%, 95% CI −3 to 28). Meta-analysis of continuous outcomes showed that probiotics reduced IBS symptoms, abdominal pain, and flatulence but not bloating or urgency (Table). 6 trials (n = 267) reported no adverse events in either probiotic or control groups; meta-analysis of 3 trials (n = 407) showed no difference between groups in adverse events (relative risk 0.93, CI 0.64 to 1.36).
Probiotics reduce symptoms of the irritable bowel syndrome in adults.
Probiotics vs placebo for the irritable bowel syndrome (IBS) in adults*
*SMD = standardized mean difference; other abbreviations defined in Glossary. Probiotic event rate, RRR, NNT, and CI calculated from data in article using a random-effects model.
†Significant heterogeneity I2 = 68%. Possible publication bias (Egger test −2.97, CI −5.54 to −0.41)
van Zanten SV. Review: Probiotics improve symptoms in adults with the irritable bowel syndrome. Ann Intern Med. ;153:JC3–7. doi: 10.7326/0003-4819-153-6-201009210-02007
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Published: Ann Intern Med. 2010;153(6):JC3-7.
Gastroenterology/Hepatology, Irritable Bowel Syndrome.
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