Single-anastomosis duodenoileal bypass versus one-anastomosis gastric bypass: 1-year results of the OASIS randomized trial
In brief
One-anastomosis gastric bypass causes five times more late complications than SADI-S
At one year, both procedures produced similar excess weight loss (about 80%) and metabolic improvement in patients with BMI 45-50, but late complications occurred in 35% of OAGB patients versus 7% after SADI-S, mainly bile-reflux events. The trade-off between frequency and severity of complications suggests procedure choice should be individualized, with longer-term data still needed.
- Journal
- Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery (Q1)
- Published
- 17 July 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Sergi Sanchez-Cordero, Ruth Lopez-Gonzalez, Paula Garcia, Jordi Castellvi, Jordi Pujol-Gebelli
- PMID
- 42567777
- DOI
- 10.1016/j.soard.2026.07.007
Why clinicians should know about it
- Picked for Bariatric and Metabolic Surgery (top studies of the week, 11 October 2026): SADI-S vs OAGB head-to-head weight loss
Abstract
BACKGROUND: Single-anastomosis duodenoileal bypass with sleeve gastrectomy (SADI-S) and one-anastomosis gastric bypass (OAGB) are increasingly used bariatric procedures, but high-quality comparative evidence remains limited. OBJECTIVES: To compare 1-year efficacy and safety outcomes of SADI-S and OAGB as primary bariatric procedures in patients with severe obesity. SETTING: Secondary care bariatric surgery center. METHODS: This was a single-center, prospective, randomized, single-blind controlled trial. Ninety-nine patients aged 18-65 years with body mass index (BMI) 45-50 kg/m2 were enrolled between 2023 and 2024; 90 underwent surgery (43 SADI-S; 47 OAGB). Patients were randomly assigned (1:1) using a computer-generated sequence. The primary outcome was excess weight loss (EWL) at 1 year. The secondary outcomes included total weight loss (TWL), BMI, late complications (>30 days), comorbidity resolution, nutritional deficiencies, and quality of life. RESULTS: At 1 year, no significant differences were observed between groups in EWL (84.34% vs 79.61%; P = .209), TWL (35.85% vs 33.02%; P = .075), or BMI (27.93 vs 28.92 kg/m2; P = .168). Comorbidity resolution rates were comparable. Nutritional deficiencies were infrequent (7.3% vs 4.3%; P = .878), with all cases related to iron deficiency. Late complications were significantly more frequent after OAGB (35.4% vs 7.1%; P = .0003), mainly related to bile reflux and managed conservatively or endoscopically. SADI-S was associated with fewer complications but included two cases requiring surgical reintervention. One death occurred in the SADI-S group and was not directly attributable to the procedure. Quality of life improved similarly in both groups. CONCLUSIONS: SADI-S and OAGB achieved comparable weight loss and metabolic outcomes at 1 year in patients with BMI 45-50 kg/m2 but showed distinct complication profiles. OAGB was associated with a higher rate of bile reflux-related events, whereas SADI-S had fewer but more severe complications. These findings support an individualized approach to procedure selection. Longer-term follow-up is required.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.