Efficacy of probiotics in patients with morbid obesity undergoing bariatric surgery - systematic review and meta-analysis

Abstract Bariatric surgery is considered effective for morbid obesity and probiotic supplementation might provide some benefits. We aimed to revise the evidence regarding probiotic supplementation in patients with morbid obesity undergoing bariatric surgery. MEDLINE, Embase, Web of Science, CENTRAL, and trial registers were searched up to 1 April 2020. We included randomized controlled trials (RCTs) and controlled clinical trials (CCT), and outcomes of interest were: weight change, quality of life (QoL), gastrointestinal symptoms, and adverse events. All stages of the review were done by two authors independently and we followed Cochrane Handbook guidance. We screened 2,541 references and included 5 studies. Probiotics may have minor to no effect with regard to %Excess weight loss at 6 weeks (mean difference (MD) 0.28, 95% CI -9.53 to 10.09; 44 participants, 2 studies), 3 months (MD 5.47, 95% CI -3.22 to 14.17; 165 participants, 3 studies), 6 months (MD 0.46, 95% CI -8.14 to 9.07; 115 participants, 2 studies), and 12 months post-surgery (MD 0.35, 95% CI -8.66 to 9.37; 123 participants, 2 studies). We observed short-term improvement in gastrointestinal symptoms. There was no important effect on QoL, and no meaningful adverse events. As probiotic supplementation might provide some benefit with respect to weight loss, might alleviate some gastrointestinal symptoms, and is associated with minor or no adverse events, continuous supplementation might be worth considering in certain individuals. Our findings are based on the body of evidence of very low certainty and further well-designed RCTs are required to elucidate the effect and strengthen the certainty in the estimates.