Evaluation of the Long-term Efficacy and Safety of the Omega Loop Bypass Versus the Roux-en-Y Gastric Bypass on the Cohort of Patients Included in the Randomized Trial YOMEGA (DGOS 13-0037)

Over the last 40 years, the Roux-en-Y Gastric Bypass (RYGB) has been the gold standard in the surgical management of morbid obesity. and is a validated bariatric procedure in France. Nevertheless, the RYGB remains a technically demanding procedure; thus and in order to overcome the complexity of this intervention, a simpler technique based on a single anastomosis at 200cm from the Treitz angle creating an omega loop (Mini Gastric Bypass - MGB or One Anastomosis Gastric Bypass-OAGB) has gradually spread around the worl without prior evaluation, . In 2018, the MGB was officially recognized by the International Federation of Bariatric Surgery (IFSO) as a standard procedure but not by the ASMBS; indeed, the OAGB remains controversial because considered by many surgeons at risk of biliary reflux and malnutrition.

In France, the national and multicenter randomized trial YOMEGA(NCT02139813), comparing the MGB to the RYGB in a prospective randomized fashion confirmed the non-inferiority of MGB compared to the RYGB in terms of weight loss at 24 months. However, significantly more complications (notably at the nutritional level) were observed in the MGB arm.After the publication of these results in September 2019, the High Authority for health (HAS) in France considered that the MGB 200cm did not constitute a validated technique nor an alternative to the RYGB, due to the worrying safety signals. Reimbursement of the MGB was also put into question by the national insurance health care system.

Nevertheless, the use and advantages of the MGB remain a hot topic with several retrospective data showing that a shorter biliopancreatic loop (150cm) would present a lower nutritional risk and excellent weight and metabolic results. A randomized trial comparing the MGB 150cm to the RYGB will thus begin soon in France (YOMEGA-2). The HAS recommends evaluating its efficacy in terms of long-term weight loss, the resolution of comorbidities but also safety outcomes. Finally, patients who have already been operated by MGB must benefit from follow-up with particular vigilance in the detection of nutritional complications and cancer of the lower esophagus. MGB could also turn out to be less expensive than RYGB: shorter operating time and better control of metabolic diseases The scientific community are still awaiting long-term data to reconsider the place of the MGB in the surgical management of obese patients. The aim of our study is to provide long-term efficacy and safety data on the YOMEGA cohort comparing the MGB to the RYGB, at 5 and 7 years of follow-up.