Long-Term Outcomes of One-Anastomosis Gastric Bypass in Class IV and Class V Obesity: A Comparative Analysis with Sleeve Gastrectomy

Abstract

Introduction: Metabolic and bariatric surgery (MBS) is the most effective treatment for severe obesity. However, the optimal approach for patients with a BMI ≥ 50 kg/m2 remains unclear. This study compares the perioperative and long-term outcomes of one-anastomosis gastric bypass (OAGB) and sleeve gastrectomy (SG) in this high-risk population. Methods: A retrospective analysis of a prospectively maintained database was conducted, including all patients with BMI ≥ 50 kg/m2 who underwent OAGB or SG at a tertiary center between 2015 and 2024. Patients with previous MBS were excluded. Baseline characteristics, perioperative complications, weight loss outcomes, and resolution of obesity-related diseases were analyzed. Results: A total of 121 patients were included: 76 underwent SG, and 45 underwent OAGB. The mean preoperative BMI was higher, and the rate of men was lower in the SG group (55 ± 5.4 vs. 52.2 ± 2.7, p = 0.0009, and 38.2% vs. 60%, p = 0.024, respectively). Overall, 90-day postoperative complications did not differ between the groups (SG: 14.5% vs. OAGB: 11.1%, p = 0.78), nor did major complications rate (SG: 2.6% vs. OAGB: 0%, p = 0.53). One perioperative mortality was observed in the SG group (1.3%). At 5-year follow-up, OAGB patients showed significantly greater total weight loss (36.7 ± 11.3% vs. 27.1 ± 13%, p = 0.01). Conversion surgery trends were higher in SG (9.1% vs. 2.6%, p = 0.13), primarily for weight regain. Obesity-related disease resolution rates were high and comparable between groups except for hypertension resolution, which was higher in OAGB (p = 0.04). Conclusions: Both OAGB and SG are safe and effective for patients with BMI ≥ 50 kg/m2, providing substantial weight loss and disease improvement. In this study, OAGB was associated with higher weight loss outcomes. Larger multi-institutional studies are needed to confirm these findings.