Clinical and Histologic Features of Patients with Biopsy-Proven Metabolic Dysfunction-Associated Fatty Liver Disease

Background/Aims Fatty liver disease is defined as a cluster of diseases with heterogeneous etiologies, and its definition continues to evolve. The novel conceptional criteria for metabolic dysfunction-associated fatty liver disease (MAFLD) were proposed in 2020 to avoid the exclusion of a certain subpopulation, but their evaluations have been limited. We aimed to examine and compare the clinical as well as histologic features of MAFLD versus nonalcoholic fatty liver disease (NAFLD) in patients with biopsy-proven hepatic steatosis. Methods From January 2009 to December 2019, 175 patients with histology-proven hepatic steatosis and 10 with cryptogenic cirrhosis who were treated at National Taiwan University Hospital, Taipei, Taiwan, were enrolled. Patients were classified into different groups according to the diagnostic criteria of MAFLD and NAFLD. The clinical and histologic features were then analyzed and compared. Results In total, 76 patients (41.1%) were diagnosed with both MAFLD and NAFLD, 81 patients (43.8%) were diagnosed with MAFLD alone, nine patients (4.9%) were diagnosed with NAFLD alone, and 19 patients (10.3%) were diagnosed with neither. Those with MAFLD alone exhibited a higher degree of disease severity regarding histology and laboratory data than those with NAFLD alone. Advanced fibrosis was associated with the presences of hepatitis B virus infection and metabolic diseases. Conclusions The novel diagnostic criteria for MAFLD include an additional 38.9% of patients with hepatic steatosis and can better help identify those with a high degree of disease severity for early intervention than can the previous NAFLD criteria. (Gut Liver 2021;15-458)