MASLD vs. MAFLD. A narrative review

Here, the history of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis nomenclatures is summarized. Metabolic dysfunction-associated fatty liver disease (MAFLD) was coined in 2020, and metabolic dysfunction-associated steatotic liver disease (MASLD) was proposed in 2023. With this backset, the present article aims at reviewing the similarities and differences between MAFLD and MASLD through a systematic analysis of published comparative studies. MAFLD and MASLD have a complex disease spectrum comprising, further to all-cause mortality, hepatic (fibrosis, cirrhosis, and primary liver cancer) and extrahepatic outcomes (major adverse cardiovascular events, chronic kidney disease, extrahepatic cancers, type 2 diabetes, and vascular dementia). Comparative studies document that—due to its superior ability to identify liver fibrosis—MAFLD better captures mortality owing to all-causes, hepatic and extrahepatic outcomes, which are strongly associated with the severity of liver fibrosis. Moreover, MASLD is inappropriate in pediatric care, lacks specificity, tends to overdiagnosis, does not consider coexistent viral hepatitis or lean subjects, and amplifies disease heterogeneity. Collectively, the evidence presented in this narrative review supports an urgent need for the development of evidence-based guideline statements. This novel developmental process should involve not only a systematic review of the evidence, with equal contribution from all the world’s regions of stakeholders and clinical panelists, but also should use quantitative data to identify an objective-level consensus to guarantee wide adoption of the process outcomes.