Gastric bypass — weight loss and metabolic outcomes similar with OAGB versus RYGB

Bariatric surgery is an effective approach in the management of obesity. Although one anastomosis gastric bypass (OAGB) is increasingly used, the efficacy and safety outcomes in comparison to standard Roux-en-Y gastric bypass (RYGB) are debated. Results from the YOMEGA randomized trial now show that OAGB is not inferior to RYGB with respect to weight loss and metabolic improvements at 2 years. The trial included 253 individuals aged 18–65 years (n = 129 OAGB; n = 124 RYGB). After 2 years, mean percentage excess BMI loss was similar between the two groups (−87.9% for OAGB versus −85.8% for RYGB). However, there were higher numbers of serious adverse events reported in the OAGB group than in the RYGB group, with increased incidence of diarrhoea, steatorrhoea and nutritional adverse events with 200 cm biliopancreatic limb OAGB that were suggestive of malabsorptive effects.


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  1. Robert, M. et al. Efficacy and safety of one anastomosis gastric bypass versus Roux-en-Y gastric bypass for obesity (YOMEGA): a multicentre, randomised, open-label, non-inferiority trial. Lancet (2019)

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Correspondence to Katrina Ray.

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Ray, K. Gastric bypass — weight loss and metabolic outcomes similar with OAGB versus RYGB. Nat Rev Gastroenterol Hepatol 16, 262 (2019).

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