Plain language summary
Gastroenteritis is a major cause of morbidity and mortality globally and symptoms can range from mild to life-threatening. Some studies have suggested benefits of probiotics in the treatment of gastroenteritis in children whilst in adults, results are inconsistent. The aim of this systematic review and meta-analysis was to evaluate the effects of probiotics on acute and chronic gastroenteritis in adults. 35 clinical trials were included in the systematic review and 22 in the meta-analysis. Of these, 23 dealt with inflammatory bowel disease, 5 with pouchitis, 3 with antibiotic-induced diarrhoea, 2 with Helicobacter pylori infection and one each with diverticulitis and acute watery diarrhoea. 27 (77%) of studies showed some benefits of probiotic administration. The meta-analysis of 22 studies did not show a statistically significant benefit of probiotics. Although statistical analysis showed the studies to be homogenous, the authors point out that studies differed widely in aetiologies and probiotics used. A subgroup analysis of 8 studies in patients with ulcerative colitis also showed no benefit. In all studies, probiotics were well tolerated and no adverse side effects were reported. The authors concluded that further research is needed to help identify the most appropriate use of probiotics for the different types of gastroenteritis.
Expert Review
Conflicts of interest:
None
Take Home Message:
- For chronic inflammatory gastroenteritis conditions in adults, probiotics were effective in treating and preventing relapse
- In ulcerative colitis, probiotics were not effective and adverse events outweighed the benefits
- No safety concerns were found for probiotic use in any studies
- Aetiologies, disease severity and duration as well as the type of probiotics used were widely diverse.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
To date, evidence has been mixed for probiotic effectiveness in gastrointestinal syndromes associated with gastroenteritis. The aim of this study was to review current evidence on the effect of probiotics on gastroenteritis in adults.
Methods
This was a systematic review (n=35; total sample size 4577, median 44) and meta-analysis (n=22) of randomised controlled trials. Quality was assessed using CADIMA as per a rating scale (0 to 4) and standards of critical appraisal.
Results
All 35 studies on gastroenteritis included participants with chronic diarrhoea of diverse aetiologies such as IBD, antibiotic-associated, except one which had acute watery diarrhoea.
51% (n=18) of studies assessed the effects of probiotics in the treatment of ulcerative colitis (UC) and Crohn's disease (CD). 60% (n=21) used multiple strains of probiotics while the rest used single strains. Lactobacilli, Bifidobacteria, Escherichia and Streptococcus were the most common and only a few studies administered probiotics with another conventional treatment.
19 studies (55%) rated highly in terms of quality while 15 (43%) scored moderately. The majority (63%) of the 27 studies where probiotics were shown to be effective were of high quality.
Systematic review results:
- 27/53 studies (77%) showed a favourable response after using probiotics (resolution, improvement, remission or no relapse), mostly in patients with IBDs
- 7 studies (20%) found probiotics to be ineffective
- 1 study was inconclusive
- Multiple strain probiotics (VSL #3) was found to be most effective in IBD
- All administered probiotics were well tolerated with no adverse side effects although caution in immunocompromised patients was mentioned in several studies.
The meta-analysis results:
- Overall effectiveness for 22 studies (p=0.37) highlighted there was not enough evidence that the intervention was more protective than controls.
- Probiotics were not effective in UC (p = 0.28), and adverse events caused by probiotics may outweigh the benefits in studies with UC patients.
Conclusion
While benefits of effectiveness were found for probiotic use in gastroenteritis in adults, results from the systematic review and meta-analysis showed a mixed effect.
Clinical practice applications:
- Based on the systematic review, probiotics may be an effective treatment or adjuvant treatment for gastroenteritis but ineffective for around 20% of patients
- It is worth noting that combined therapy with standard treatment showed effective results
- Beneficial effects of probiotics in other key clinical outcomes including disease prevention, relapse, quality of life, morbidity were found
- While the results are interesting it is difficult to apply them in practice as the type of probiotics used were widely different as were the causes, severity and duration of gastroenteritis.
Considerations for future research:
- Further and larger studies would be beneficial to understand the benefits of probiotics in terms of single therapy or in combination with standard treatment particularly for UC, CDs, gastroenteritis not due to viral infection
- Individual-level data instead of aggregated data could give a better idea of effectiveness of probiotics in the future
- In this study aetiologies and the type, dosage, duration of probiotics used were widely diverse therefore systematic reviews and meta-analysis on specific conditions, specific probiotic strains and combinations would be beneficial.
Abstract
Probiotics have been widely used in gastroenteritis due to acute and chronic illnesses. However, evidence supporting the effectiveness of probiotics in different health conditions is inconclusive and conflicting. The aim of this study was to review the existing literature on the effects of probiotics on gastroenteritis among adults. Only original articles on clinical trials that demonstrated the effects of probiotics in adults with gastroenteritis were used for this analysis. Multiple databases, such as PubMed, Google Scholar, MEDLINE and Scopus databases, were searched for the data. The study followed standard procedures for data extraction using a PRISMA flow chart. A quality appraisal of the selected studies was conducted using CADIMA. Finally, a meta-analysis was performed. Thirty-five articles met the selection criteria; of them, probiotics were found effective in the treatment and/or prevention of chronic inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease in 17 (49%), and the treatment of pouchitis in 4 (11.4%), antibiotic-induced diarrhea in 3 (8.6%), Helicobacter pylori infection in 2 (5.7%) and diverticulitis in 1 (2.9%), while the remaining 7 (20%) were ineffective, and 1 study's results were inconclusive. The meta-analysis did not demonstrate any significant protective effects of probiotics. Having a τ2 value of zero and I2 of 6%, the studies were homogeneous and had minimum variances. Further studies are suggested to evaluate the beneficial effects of probiotics in IBDs and other chronic bowel diseases.
Methodological quality
Jadad score
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Not applicable
Allocation concealment
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Not applicable
