Clinical Outcomes of Contemporary Bariatric Surgical Procedures: A Nationwide Cohort Study

Most bariatric surgery studies have been conducted at single centers, with limited research focusing on Asian populations. In Korea, bariatric surgery has been covered by the National Health Insurance System since 2019. Using this nationally representative data, we assessed the clinical outcomes of bariatric surgery in Korea.

We included 856 individuals who underwent bariatric surgery between 2019 and 2020 with repeated health checkups before (2 years) and after (2±0.5 years) surgery. Anthropometric indicators and the prevalence of metabolic diseases were compared pre- and postoperatively. Logistic regression analysis was used to identify predictors of sufficient weight loss.

Two years post-surgery, significant reductions were observed in body weight (-22.1 kg), body mass index (BMI; -7.9 kg/m²), and waist circumference (-17.4 cm). The number of patients with study-defined diabetes and hypertension decreased by 71% (245/345) and 52% (267/513), respectively. Metabolic dysfunction-associated fatty liver disease improved in 70% of cases. Sufficient weight loss, defined as ≥20% total weight loss, was achieved by 56.3% of the study population, and 76.6% achieved ≥50% excess weight loss. Predictors of sufficient weight loss included younger age, female sex, higher baseline BMI, and higher systolic blood pressure (SBP), whereas the type of surgical procedure (Roux-en-Y gastric bypass, sleeve gastrectomy, or biliopancreatic diversion with duodenal switch) was not significantly associated with the outcome.

Bariatric surgery in Korean patients led to substantial weight loss and metabolic improvement. Greater benefits were observed in younger, female patients with higher baseline BMI and SBP.