Meta-analysis: probiotics in antibiotic-associated diarrhoea.

BACKGROUND: Diarrhoea is a common occurrence in association with antibiotic administration. Earlier studies and meta-analyses have suggested that probiotic administration reduces the incidence of antibiotic-associated diarrhoea (AAD).

AIM: To estimate the reduction in risk of AAD with administration of probiotics in randomised placebo-controlled trials and to identify factors associated with such reduction.

METHODS: 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.

RESULTS: 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).

CONCLUSIONS: This updated meta-analysis confirms earlier results supporting the preventive effects of probiotics in AAD.