“Metabolic dysfunction-associated fatty liver disease (MAFLD)” is the term suggested in 2020 to refer to fatty liver disease related to systemic metabolic dysregulation. The name change from nonalcoholic fatty liver disease (NAFLD) to MAFLD comes with a simple set of criteria to enable easy diagnosis at the bedside for the general medical community, including primary care physicians. Since the introduction of the term, there have been key areas in which the superiority of MAFLD over the traditional NAFLD terminology has been demonstrated, including for the risk of liver and extrahepatic mortality, disease associations, and for identifying high-risk individuals. Additionally, MAFLD has been adopted by a number of leading pan-national and national societies due to its concise diagnostic criterion, removal of the requirement to exclude concomitant liver diseases, and reduction in the stigma associated with this condition. The current article explores the differences between MAFLD and NAFLD diagnosis, areas of benefit, some potential limitations, and how the MAFLD terminology has opened up new fields of research.

Background/Aims: The global proportion of hepatocellular carcinoma (HCC) attributable to metabolic dysfunction-associated fatty liver disease (MAFLD) is unclear. The MAFLD diagnostic criteria allows objective diagnosis in the presence of steatosis plus defined markers of metabolic dysfunction, irrespective of concurrent liver disease. We aimed to determine the total global prevalence of MAFLD in HCC cohorts (total-MAFLD), including the proportion with MAFLD as their sole liver disease (single-MAFLD), and the proportion of those with concurrent liver disease where MAFLD was a contributary factor (mixed-MAFLD). Methods: This systematic review and meta-analysis included studies systematically ascertaining MAFLD in HCC cohorts, defined using international expert panel criteria including ethnicity-specific BMI cut-offs. A comparison of clinical and tumour characteristics was performed between single-MAFLD, mixed-MAFLD, and non-MAFLD HCC. Results: 22 studies (56,565 individuals with HCC) were included. Total and single-MAFLD HCC prevalence was 48.7% (95% confidence interval [CI] 34.5–63.0%) and 12.4% (95% CI 8.3–17.3%), respectively. In HCC due to chronic hepatitis B, C, and alcohol-related liver disease, mixed-MAFLD prevalence was 40.0% (95% CI 30.2–50.3%), 54.1% (95% CI 40.4–67.6%) and 64.3% (95% CI 52.7–75.0%), respectively. Mixed-MAFLD HCC had significantly higher likelihood of cirrhosis and lower likelihood of metastatic spread compared to single-MAFLD HCC, and a higher platelet count and lower likelihood of macrovascular invasion compared to non-MAFLD HCC. Conclusions MAFLD is common as a sole aetiology, but more so as a co-factor in mixed-aetiology HCC, supporting the use of positive diagnostic criteria.