Coexistent Hepatitis B Virus and Metabolic Dysfunction-Associated Steatotic Liver Disease Under the New Definition: A New Era for Established Diseases

Dysfunction-associated steatotic liver disease (MASLD) is a newly introduced term for the condition previously known as nonalcoholic fatty liver disease (NAFLD). MASLD affects 38% of the global population and is now diagnosed based on the presence of steatosis but also with cardiometabolic risk factors indicating metabolic dysfunction. Chronic hepatitis B (CHB), another significant public health issue, impacts over 296 million people worldwide, or approximately 3.2% of the global population. Studies have consistently reported a complex relationship between MASLD and CHB. Previous studies indicate that MASLD may protect against high viral loads, while other studies indicate that coexisting MASLD and CHB may lead to more advanced fibrosis and an elevated risk of HCC. Additionally, numerous studies highlight a strong association between CHB and metabolic syndrome components. This review article examines the relationship between CHB and MASLD, considering what has been previously published.