One anastomosis gastric bypass (OAGB) has become a widespread technique over the last few years in France, without any prior assessment and despite existing controversies among bariatric surgeons. An older bypass technique for treating obesity, the Roux-en-Y gastric bypass (RYGB), is available and reimbursed, having been assessed and approved for use in 2005. In 2019, the French Haute Autorité de Santé (HAS) assessed OAGB for the treatment of severe and massive obesity. This assessment, the first in the world, was undertaken for OAGBs carried out with a 200- or 150-centimeter biliopancreatic-limb (BP-limb) length.

A systematic review (SR) of the literature and consultation of a working group consisting of both healthcare professionals (clinician and surgeons) and patients were carried out. The primary aim of our assessment was to determine whether the OAGB technique can replace RYGB. The efficacy and safety profile of OAGB was compared with RYGB in adult patients with massive, severe obesity. Complications and postoperative follow up specific to OAGB were identified.

The three selected randomized controlled trials (RCTs) could not confirm the superiority or the non-inferiority of OAGB, compared with RYGB, on the selected efficacy endpoints of weight loss, resolution of comorbidities, and quality of life. Adverse events reported for OAGB included severe nutritional complications and bile reflux that could potentially lead to lower esophageal cancer. In one RCT, the frequency of serious adverse events in the OAGB group was almost two times higher than in the RYGB group.

HAS considered that OAGB carried out with a longer (200 centimeter) BP-limb is not a validated technique for the surgical treatment of massive, severe obesity. Thus, it cannot be considered an alternative to RYGB. There were insufficient data available on OAGB performed with a 150-centimeter BP-limb. Thus, HAS recommended undertaking a multicenter RCT to assess the efficacy and safety of OAGB. Patients who have already undergone OAGB should receive the same follow up as patients who have received RYGB, including close monitoring for nutritional complications and lower esophageal cancer and an endoscopic examination five years after surgery.