Metabolic-associated Fatty Liver Disease.

A panel of experts from 22 countries recently proposed a name change from nonalcoholic fatty liver disease (NAFLD) to metabolic-associated fatty liver disease, or MAFLD.1 Subsequently, new criteria for diagnosing MAFLD were provided to help guide clinicians in their clinical practice.2 The criteria are based on evidence of hepatic steatosis in the presence of one or more of overweight/obesity, type 2 diabetes, or metabolic dysregulation.3 The proposed novel diagnostic criteria represent a landmark in hepatology that combines our current understanding of obesity, metabolic syndrome and system biology into a single focus.4,5

MAFLD is highly prevalent, affecting more than a quarter of the world’s population. The prevalence in Asia is following a trajectory similar to that in the western countries, with China having a projected burden of 314 million cases by 2030,6 but disease awareness and public response in government funding have been inadequate for decades. The current problems are partially attributable to a difficult diagnosis when using the criteria for NAFLD because a range of other conditions such as excess alcohol consumption, viral hepatitis, or immune mediated liver injury must first be excluded. The need to rule out competing etiologies for fatty liver disease may prove to be counter-intuitive, as hepatologists often find chronic hepatitis B infection coexistent with liver steatosis. Conversely, a diagnosis of MAFLD allows for inclusion of mixed etiologies, such as viral hepatitis, which is a new way of thinking about fatty liver disease,7 while establishing a conceptual framework to consider other etiologies that might contribute to and worsen the liver condition.

It is likely that the general adoption of MAFLD will be challenging, and will require focused efforts by all stakeholders such as academics, practitioners, medical organizations, and policy makers.8–12 Debates that take evidence-based medicine into account may encourage others to consider alternate viewpoints, and contribute to an informed clinical decision.13–15 Therefore, in recognition of the pivotal importance of improved knowledge of fatty liver disease, the Journal of Clinical and Translational Hepatology has sought to provide a forum for the MAFLD vs. NAFLD debate. As the guest editor, I undertook the task of creating a special issue grounded in the science contributing to the MAFLD discussion. Since January 2021, we received over 23 reviews, meta-analyses, experimental, and clinical studies from 11 countries. Fourteen have been accepted for publication following editorial and blinded peer review (Fig. 1).

Fig. 1

MAFLD studies included in a special issue of the Journal of Clinical and Translational Hepatology.

MAFLD, metabolic-associated fatty liver disease.

Transitioning from NAFLD to MAFLD may be beneficial, but the new definition should not be adopted without careful consideration. Indeed, discussion of the critical evidence is ongoing, especially the lack of exclusion of confounding conditions in the definition of MAFLD. It has led so far to numerous position statements published by liver societies and organizations worldwide. In China, a group of hepatologists and gastroenterologists representing 31 administrative regions organized by the Chinese Society of Hepatology, conducted a survey to consider before endorsing the MAFLD terminology.16 In the survey, 95.45% of participants approved the name change and 75.76% supported the updated diagnostic criteria for MAFLD. Endorsement of the MAFLD terminology has been obtained in Asia, Latin America, the Middle East, and Africa.3,17–19 The journal seeks to provide insightful articles that may improve the understanding and awareness of the disease, with the hope of promoting translation of research outcomes from research to better care of MAFLD patients.