Meta-analysis: probiotics in antibiotic-associated diarrhoea

Alimentary Pharmacology and Therapeutics, 05/07/2012

This updated meta–analysis confirms earlier results supporting the preventive effects of probiotics in antibiotic–associated diarrhoea (AAD).


  • Meta-analysis of randomised, double-blinded, placebo-controlled trials including patients treated with antibiotics and administered a probiotic for at least the duration of the antibiotic treatment.
  • The outcome was incidence of diarrhoea irrespective of the presence of Clostridium difficile or the development of pseudomembranous colitis.
  • Meta-analysis and meta-regression methods were used to synthesise data and to assess influence of: mean age, duration of antibiotics, risk of bias and incidence of diarrhoea in the placebo group on outcomes.
  • Subgroup analyses explored effects of different probiotic species, patient populations and treatment indications.


  • A total of 34 studies were included with 4138 patients.
  • The pooled relative risk (RR) for AAD in the probiotic group vs. placebo was 0.53 (95% CI 0.44-0.63), corresponding to a number needed to treat (NNT) of 8 (95% CI 7-11).
  • The preventive effect of probiotics remained significant when grouped by probiotic species, population age group, relative duration of antibiotics and probiotics, study risk of bias and probiotic administered.
  • The pooled RR for AAD during treatment for Helicobacter pylori (H. pylori) was 0.37 (95% CI 0.20-0.69), corresponding to a NNT of 5 (95% CI 4-10).

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