Safety, Efficacy, and Quality of Life Outcomes of Bariatric and Metabolic Surgery in Korea: A Prospective Multicenter Cohort Study

Introduction: This prospective multicenter cohort study aimed to assess the effectiveness and safety of bariatric and metabolic surgery (BMS) in Korean patients with class II obesity or higher and those with a body mass index (BMI) ≥ 27.5 kg/m². Methods: Between September 2020 and December 2022, 116 patients undergoing BMS were enrolled from nine centers in Korea. Of these, 37 patients underwent gastric bypass and 79 underwent sleeve gastrectomy. Follow-up evaluations were performed for up to 2 years. Clinical data were collected alongside four quality of life (QOL) surveys (EQ-5D, IWQOL-lite, OP-scale, and BAROS) administered at 12, 24, 48, 72, and 96 weeks postoperatively. Clinical parameters included obesity severity, complications by surgery type, associated medical problems, nutritional status, and their longitudinal changes. Results: The cohort had a mean age of 37.0 ± 11.1 years and a mean BMI of 41.9 ± 7.6 kg/m²; 71.6% of participants were female. Baseline associated medical problems included type 2 diabetes mellitus (T2DM) in 45 patients (38.8%), hypertension in 77 (66.4%), and hyperlipidemia in 77 (66.4%). Total weight loss reached 26.8% at 1 year, 27.5% at 1.5 years, and 24.7% at 2 years. Remission rates for T2DM, hypertension, and hyperlipidemia at 1 year were 80.7%, 50.0%, and 49.0%, respectively, increasing to 85.7%, 50.0%, and 71.4% at 2 years. No significant differences were observed between the procedures in postoperative weight trajectories, nutritional outcomes, or improvements of associated medical problem. All QOL scores showed significant and sustained improvement across all surveys. The overall complication rate was 12.1% (early: 0.9%, late: 11.2%), which was considered acceptable. Conclusion: Gastric bypass and sleeve gastrectomy are effective and safe BMS procedures for Korean patients, providing substantial weight loss, remission of associated medical problems, and improved QOL.