Bariatric Surgery Outcomes in People with Severe Obesity (BMI ≥ 50 kg/m2)

Abstract Introduction The benefits of metabolic bariatric surgery (MBS) in people with body mass index (BMI) ≥50kg/m² are not well-established, with concerns of increased risk and poorer weight loss. Optimal surgical type (gastric bypass [GB] versus sleeve gastrectomy [SG]) is unclear, with studies comparing complication rates, weight loss, and glycemic outcomes reporting mixed results. Methods Participants with BMI≥50kg/m² undergoing MBS (SG or GB) from 2008-2022 were recruited. Demographics, anthropometrics, biochemistry and diabetes status were analysed at baseline, 12-months, and 24-months post-operatively. Surgical outcomes and complications were analysed. Results The study included n=184 with BMI≥50kg/m² (57.6% female, age 38.6±10.5years, BMI 55.3±6.0kg/m²). Pre-operatively, 21.1% had pre-diabetes and 33.2% had diabetes (mean HbA1c 8.0±1.7%). Most subjects (89.1%) underwent SG. The overall 30-day adverse event rate was 4.9%, higher in GB group (GB=15%, SG=3.7%, p=0.061). The GB group had longer length of stay (GB =4.5±0.6days, SG=3.1±0.2, p=0.023). The 30-day readmission rate was 2.2%, and rate of revisional surgery was 2.7%, with no significant difference between groups. The follow-up rate was 67.9% at 12-months, 51.1% at 24-months. Average %total weight loss at 12-months (27.4±9.0%, SG=27.6±9.0%, GB=26.0±9.4%, p=0.481) and 24-months (27.1±10.9%, SG=27.4±11.1%, GB=24.9±8.9%, p=0.495) were similar between groups. The GB group had a larger HbA1c reduction (3.2±1.1%) than SG (1.9 ±1.3%, p=0.030), but no difference in diabetes remission rates (69.2% at 12-months, 76.7% at 24-months). Conclusion MBS is safe and effective for individuals with BMI≥50kg/m², with good weight loss and glycemic outcomes with both SG and GB. Complication rates were low, although higher in the GB group.