Prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD) in Korean Patients Undergoing Bariatric Surgery

Purpose: The number of Korean patients undergoing metabolic surgery for obesity is on the increase. Patients undergoing obesity and metabolic surgery have a body mass index (BMI) ≥30 kg/m². In this study, we investigated the prevalence of nonalcoholic fatty liver disease in Korean patients who had undergone bariatric surgery.

Materials and methods: Between January 2019 and December 2021, 147 patients who underwent bariatric surgery were studied. Of these, 133 patients underwent transient elastography, and the prevalence was analyzed after being classified using the World Health Organization (WHO) obesity classification system. The participants were divided into three groups as Class 1, BMI 30 to <35 kg/m²; Class 2, BMI 35 to <40 kg/m²; and Class 3, BMI ≥40 kg/m²).

Results: The average ages of three classes of patients according to the WHO obesity classification system were 42.4, 38.8, and 36.0 years with intergroup differences. Controlled attenuation parameter (CAP) and liver stiffness also showed differences in each group (307.6±59.3, 325.8±53.0, and 346.5±52.2, respectively, P=0.007; CAP, 5.5±2.1, 7.1±3.8, and 11.7±9.1, P<0.001; liver stiffness). The prevalence of type 2 diabetes mellitus also differed among the groups (61.3%, 42.2%, and 36.8%, respectively, P=0.036). The proportion of patients with liver fibrosis also showed differences in each group (16.1%, 42.2%, and 59.6%, respectively; P<0.001).

Conclusion: Our study shows that most Korean patients undergoing bariatric surgery were also diagnosed with hepatic steatosis. Furthermore, the rate of liver fibrosis was higher among patients with more severe obesity.