Probiotics for the Treatment of Asthma: A Systematic Review and Meta-Analysis of Randomized Trials

Background: Asthma is a growing problem worldwide and the limitations of the current therapy for allergic asthma highlight the need for novel therapeutics. We conducted a systematic review and meta-analysis to find out the role of probiotics in the treatment of Asthma. Materials and Methods:  In this systematic review, a comprehensive search of the major electronic databases was done till October 2017. Clinical trials comparing the effect of probiotics versus placebo on treating asthma were included. Trials focusing on prevention of asthma were not included. A predefined set of outcome measures was assessed. Continuous data were expressed as standardized mean difference with 95% confidence interval (CI). Dichotomous data were expressed as odds ratio with 95% CI. P-value < 0.05 was considered as significant. Results: 11 studies with 2,027 participants were included. Probiotic intake was associated with a significant improvement in pulmonary function test and slight benefits in asthma control test. Probiotics did not reduce asthma exacerbation and wheezing episodes although there was a high degree of heterogeneity in studies. It also has no significant effect on viral respiratory infection in asthmatics and no improvement in quality of life. Probiotic intake improved the following parameters: longer time free from episodes of asthma. Adverse events were not significant. Conclusion: Although trials showed promising effects of probiotics as an additive on therapy on some parameters of asthma, as this evidence was generated from only a few trials with high degree of heterogeneity, routine use of probiotics as an additive on therapy of asthmatic patients cannot be recommended at this time.