Clinical Report: Transitioning from NAFLD to MASLD in Liver Disease Nomenclature

Overview

The nomenclature for nonalcoholic fatty liver disease (NAFLD) has been updated to metabolic dysfunction–associated steatotic liver disease (MASLD) to better reflect the metabolic origins and reduce stigmatization. MASLD diagnosis requires liver steatosis plus at least one metabolic risk factor, and introduces a new category, MetALD, for patients with combined metabolic and alcohol-related liver disease.

Background

NAFLD was traditionally defined by hepatic fat accumulation exceeding 5% of hepatocytes without other causes such as significant alcohol intake. It encompassed a spectrum from simple steatosis to steatohepatitis and fibrosis. However, NAFLD was a diagnosis of exclusion and did not incorporate metabolic dysfunction explicitly, despite strong associations with metabolic syndrome features like obesity, diabetes, and dyslipidemia. Insulin resistance and hyperinsulinemia play key roles in hepatic lipid accumulation, driving disease progression.

Data Highlights

The updated MASLD definition requires hepatic steatosis plus at least one of five cardiometabolic risk factors. Alcohol consumption limits remain defined as ≥30 g/day for men and ≥20 g/day for women. The new MetALD category recognizes patients with steatosis and alcohol intake above these thresholds, acknowledging combined metabolic and alcohol-related contributions to liver disease and associated increased mortality risk.

Key Findings

• The term NAFLD was limited by its exclusionary nature and stigmatizing language ('nonalcoholic' and 'fatty').
• MASLD nomenclature emphasizes metabolic dysfunction as the primary driver, requiring at least one metabolic risk factor for diagnosis.
• The new category MetALD identifies patients with both metabolic dysfunction and elevated alcohol intake, a group with higher mortality risk.
• The Delphi consensus process included multiple stakeholders and patient input to ensure transparency and acceptance.
• MASLD retains the concept of steatohepatitis, now termed MASH, and excludes patients exceeding alcohol consumption thresholds to protect biomarker and drug development.
• Mass population screening for MASLD is not currently recommended; focus remains on case-finding advanced fibrosis in high-risk groups such as diabetics with elevated liver enzymes.

Clinical Implications

Clinicians should adopt MASLD terminology to better reflect the metabolic basis of steatotic liver disease and reduce stigma. Recognition of MetALD highlights the need to evaluate both metabolic and alcohol-related risk factors in patients. Screening efforts should prioritize high-risk populations for fibrosis assessment rather than general population screening.

Conclusion

The transition from NAFLD to MASLD represents a paradigm shift emphasizing metabolic dysfunction and improving disease classification. This change facilitates clearer diagnosis, reduces stigma, and opens new avenues for research, particularly regarding the interplay of metabolic and alcohol-related liver disease.

References

1. Eslam et al. 2020 -- Proposal to rename NAFLD to MAFLD
2. Multisociety Consensus 2023 -- Adoption of MASLD nomenclature