Probiotics for the prevention of antibiotic-associated diarrhea and Clostridium difficile infection among hospitalized patients: systematic review and meta-analysis.

Background: Antibiotic-associated diarrhea (AAD) and Clostridium difficile infection (CDI) are associated with high morbidity, mortality, and health care costs. Probiotics may mitigate the existing disease burden. We performed a systematic review and meta-analysis to evaluate the efficacy of co-administration of probiotics with antibiotics in preventing these adverse outcomes in adult inpatients.

Methods: Systematic searches of MEDLINE (1946 to May 2012), Embase (1980 to May 2012), and the Cochrane Central Register of Controlled Trials were undertaken on May 31, 2012, to identify relevant publications. We searched for randomized controlled trials, published in English, of adult inpatients who were receiving antibiotics and who were randomly assigned to co-administration of probiotics or usual care, with or without the use of placebo. Studies were included if they reported on AAD or CDI (or both) as outcomes. Data for predetermined criteria evaluating study characteristics, methods, and risk of bias were extracted. Trials were given a global rating of good, fair, or poor by at least 2 reviewers. Meta-analyses were performed using a random-effects model, and pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated.

Results: Sixteen trials met the criteria for inclusion in this review. Four studies were of good quality, 5 were of fair quality, and 7 were of poor quality. Pooled analyses revealed significant reductions in the risks of AAD (RR 0.61, 95% CI 0.47 to 0.79) and CDI (RR 0.37, 95% CI 0.22 to 0.61) among patients randomly assigned to co-administration of probiotics. The number needed to treat for benefit was 11 (95% CI 8 to 20) for AAD and 14 (95% CI 9 to 50) for CDI. With subgroup analysis, significant reductions in rates of both AAD and CDI were retained in the subgroups of good-quality trials, the trials assessing a primarily Lactobacillus-based probiotic formulation, and the trials for which the follow-up period was less than 4 weeks.

Interpretation: Probiotics used concurrently with antibiotics reduce the risk of AAD and CDI.