Revisional OAGB Versus SADI-S After Failed Bariatric Surgery: A Comparative Study of Metabolic, Nutritional, and Quality-of-Life Outcomes

Background: Revisional bariatric surgery is increasingly performed due to inadequate weight loss, weight regain, or complications following primary bariatric procedures. One anastomotic gastric bypass (OAGB) and single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) are commonly used revisional options, yet comparative data on metabolic, nutritional, and quality-of-life outcomes remain limited. Objective: To compare metabolic, nutritional, perioperative, and quality-of-life outcomes between revisional OAGB and SADI-S. Methods A retrospective comparative cohort study was conducted at a tertiary bariatric center between 2020 and 2025. Adult patients undergoing revisional OAGB or SADI-S after primary failed sleeve gastrectomy were included. Outcomes included weight loss, metabolic and nutritional parameters, perioperative outcomes, complications, and quality of life assessed using BAROS and SF-BARI questionnaires. Results Forty-four patients were included (22 OAGB, 22 SADI-S). At one year, weight loss outcomes were comparable between groups (EWL 43% vs. 37%, p > 0.9; TWL 18% vs. 15%, p = 0.9). SADI-S demonstrated superior lipid profile improvement, including lower total cholesterol (119 vs. 153 mg/dL, p = 0.005) and LDL levels (65 vs. 85 mg/dL, p = 0.032). Vitamin B12 levels were higher after SADI-S (475 vs. 330 pg/mL, p = 0.015), while other nutritional parameters were comparable. Operative time was shorter for OAGB (90 vs. 109 minutes, p = 0.019). Quality-of-life scores were similar between groups. Conclusion Both revisional OAGB and SADI-S are safe and effective procedures with comparable weight loss and quality-of-life outcomes. SADI-S provides greater metabolic benefit, particularly in lipid profile improvement, while OAGB demonstrates a more favorable nutritional profile. Procedure selection should be individualized based on metabolic needs and nutritional risk.