Effectiveness of probiotics on the occurrence of infections in older people: systematic review and meta-analysis

Background: infectious diseases in older people are associated with higher mortality rates and probiotics have been hypothesised to reduce the occurrence of infection. Objectives: to assess the effectiveness and safety of probiotics in the occurrence of infections in older adults in comparison to placebo. Methods: a systematic review and meta-analysis of randomised placebo-controlled trials were conducted on 30 December 2016 using Medline, Embase, CENTRAL, Web of Science and LILACS databases. Efficacy outcomes were: occurrence of infection, quality of life, mortality and mean duration of infection per episode. Safety outcomes were adverse events. Data were analysed using relative risk ratios with 95% confidence intervals. Relative risk ratios were pooled where more than three estimates were available. Results: fifteen articles were included, with a total of 5,916 participants with a mean age of 75.21 years. The effect of probiotics was not significantly different from that reported for placebo on the occurrence of infection, adverse events, mortality or mean duration of infection episodes (relative risk (RR) 0.90, 95% confidence interval (CI) 0.76 to 1.08; RR 1.01, 95% CI 0.91 to 1.12; RR 1.09, 95% CI 0.70 to 1.72; MD -0.35, 95% CI -1.57 to 0.87, respectively). Conclusion: the current low-quality evidence does not support the use of probiotics for the reduction in the occurrence of infection in older adults, however, the safety outcomes were similar between probiotics and placebo. Further research is required to confirm these findings. PROSPERO: CRD42014013707