When was Metabolic Associated Fatty Liver Disease (MAFLD) proposed?

When Was MAFLD Created?

The term Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD) was first proposed in 2020 as a replacement for the older term Non-Alcoholic Fatty Liver Disease (NAFLD). 1, 2

Evolution of Terminology

The evolution of fatty liver disease terminology has undergone several important changes:

1. 2020: Initial MAFLD Proposal

   • International expert panels proposed MAFLD to better reflect the pathogenic role of metabolic dysfunction
   • This represented a shift from the negative definition of NAFLD (absence of alcohol) to a positive definition based on metabolic risk factors

2. 2023: Transition to MASLD

   • A modified Delphi process led by three major liver associations resulted in consensus to rename the condition as Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) 3, 4
   • This change was established through a multi-society guided process to further refine the nomenclature

Key Differences in Diagnostic Criteria

The transition from NAFLD to MAFLD/MASLD represented a fundamental shift in diagnostic approach:

• NAFLD (previous terminology): Defined by exclusion - liver steatosis without significant alcohol consumption or other secondary causes
• MAFLD/MASLD (current terminology): Defined by inclusion - requires both:
  • Evidence of hepatic steatosis (by imaging or biopsy)
  • Presence of at least one cardiometabolic risk factor 5

Clinical Implications of the New Terminology

The change in terminology has several important clinical implications:

• Broader patient identification: Studies show MAFLD criteria identify more individuals with fatty liver disease than NAFLD criteria 2
• Higher risk stratification: Patients identified using MAFLD criteria are associated with higher risks of hepatic fibrosis compared to NAFLD 2
• Recognition of metabolic comorbidities: The new terminology better acknowledges the relationship between liver disease and metabolic dysfunction 3

Current Nomenclature Framework

As of 2024, the most current guidelines use MASLD as the preferred terminology:

• MASLD is defined as hepatic steatosis with at least one cardiometabolic risk factor and no other discernible cause 3
• If inflammation and hepatocyte ballooning are present on histology, the condition is termed Metabolic Dysfunction-Associated Steatohepatitis (MASH) 3
• A separate category called MetALD (Metabolic dysfunction and Alcoholic Liver Disease) was created for cases with both metabolic risk factors and moderate alcohol consumption 3

The transition from NAFLD to MAFLD in 2020, and subsequently to MASLD in 2023, represents an important evolution in our understanding of fatty liver disease, shifting focus from what the disease is not (non-alcoholic) to what it actually is (metabolically driven).