Probiotics for the Prevention of Ventilator-Associated Pneumonia: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND: Ventilator-associated pneumonia (VAP) is a common and serious complication of mechanical ventilation. We conducted a meta-analysis of published randomized controlled trials to evaluate the efficacy and safety of probiotics for VAP prevention in patients who received mechanical ventilation. METHODS: We searched a number of medical literature databases to identify randomized controlled trials that compared probiotics with controls for VAP prevention. The results were expressed as odds ratios (OR) or mean differences with accompanying 95% CIs. Study-level data were pooled by using a random-effects model. Data syntheses were accomplished by using statistical software. RESULTS: Fourteen studies that involved 1,975 subjects met our inclusion criteria. Probiotic administration was associated with a reduction in VAP incidence among all 13 studies included in the meta-analysis (OR 0.62, 95% CI 0.45-0.85; P = .003; I-2 = 43%) but not among the 6 double-blinded studies (OR 0.72, 95% CI 0.44-1.19; P = .20; I-2 = 55%). We found a shorter duration of antibiotic use for VAP (mean difference 21.44, 95% CI 22.88 to 20.01; P = .048, I-2 = 30%) in the probiotics group than in the control group, and the finding comes from just 2 studies. No statistically significant differences were found between the groups in terms of ICU mortality (OR 0.95, 95% CI 0.67-1.34; P = .77; I-2 = 0%), ICU stay (mean difference -0.77, 95% CI -2.58 to 1.04; P = .40; I-2 = 43%), duration of mechanical ventilation (mean difference -0.91, 95% CI -2.20 to 0.38; P = .17; I-2 = 25%), or occurrence of diarrhea (OR 0.72, 95% CI 0.45-1.15; P = .17; I-2 = 41%). CONCLUSIONS: The meta-analysis results indicated that the administration of probiotics significantly reduced the incidence of VAP. Furthermore, our findings need to be verified in large-scale, well-designed, randomized, multicenter trials.