Metabolic Dysfunction-associated Fatty Liver Disease (MAFLD) and Viral Hepatitis

A new definition of metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed in 2020. The change from nonalcoholic fatty liver disease (NAFLD) to MAFLD highlights the metabolic abnormalities that accompany fatty liver. The diagnosis of MAFLD does not require exclusion of secondary causes of liver diseases and alcohol consumption. Thus, MAFLD may coexist with other types of liver diseases, such as viral hepatitis, a disease that remains the most common cause of liver disease-related death. With the increasing prevalence of MAFLD, patients with coincidental MAFLD and viral hepatitis are frequently encountered in clinical practice. In this review, we mainly summarize the mutual relationship between hepatitis B/C and systematic metabolism dysfunction related to MAFLD. We discuss the impact of MAFLD on progression of viral hepatitis and the therapies. Some unaddressed clinical problems related to concomitant MAFLD and viral hepatitis are also identified.