Supplementary Material for: The One Anastomosis Gastric Bypass is a suitable alternative to Roux-en-Y Gastric Bypass in patients with BMI > 50 kg/m2 : a propensity-score matched analysis

Introduction: Body Mass Index (BMI) ≥ 50 kg/m2 is more challenging for the bariatric surgeon, because of a thicker abdominal wall, more visceral fat, and hepatomegaly by liver steatosis. This study aims to give an overview of 5-year outcomes after OAGB and RYGB in these patients in terms of weight loss, remission of comorbidities, and complications. Methods: This retrospective single-center cohort study focused on patients with BMI ≥ 50 kg/m2 undergoing OAGB or RYGB between 2015 and 2017 at a non-academic teaching hospital in the Netherlands. A 1:1 propensity-score matched (PSM) comparison was conducted. Results: In total, 158 patients underwent OAGB and 32 patients RYGB. After performing a 1:1 PSM, we obtained two nearly identical cohorts of 28 patients. Follow-up data after five years was available in 79% of the patients after OAGB and 82% of the patients after RYGB. Both procedures resulted in equal weight loss, remission of comorbidities, and short-term complications. More minor mid-term complications were seen after OAGB (50% versus 18%; p=0.011) due to reflux complaints (50% versus 7%; p<0.001). The number of patients with major mid-term complications did not differ (7% after OAGB versus 14% after RYGB; p=0.388). The only major complication after OAGB was conversion to RYGB due to reflux in 7.1% of the patients. In contrast, major complications following RYGB were more diverse. Conclusion: Both procedures resulted in similar weight loss, remission of comorbidities, short-term complications, and major mid-term complications; making OAGB a suitable alternative to RYGB for patients with a BMI > 50 kg/m2.