Systematic Reviews
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 21, 2023; 29(3): 549-560
Published online Jan 21, 2023. doi: 10.3748/wjg.v29.i3.549
Metabolic dysfunction associated fatty liver disease: The new nomenclature and its impact
Si-Ying Tang, Jian Shiun Tan, Xian-Zheng Pang, Guan-Huei Lee
Si-Ying Tang, Guan-Huei Lee, Division of Gastroenterology and Hepatology, National University Hospital, Singapore 119228, Singapore
Jian Shiun Tan, Xian-Zheng Pang, Yong Loo Lin School of Medicine, Singapore 117597, Singapore
Author contributions: Tang SY, Tan JS and Pang XZ contributed equally to this work; Tang SY, Tan JS, Pang XZ and Lee GH designed the research study; Tang SY, Tan JS and Pang XZ performed the research; Tang SY, Tan JS, Pang XZ and Lee GH analyzed the data and wrote the manuscript; and all authors have read and approve the final manuscript.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Guan-Huei Lee, FRCP, MBBS, MRCP, PhD, Assistant Professor, Attending Doctor, Doctor, Division of Gastroenterology and Hepatology, National University Hospital, 1E, Kent Ridge Road, Singapore 119228, Singapore. guan_huei_lee@nuhs.edu.sg
Received: September 24, 2022
Peer-review started: September 24, 2022
First decision: October 30, 2022
Revised: November 14, 2022
Accepted: December 23, 2022
Article in press: December 23, 2022
Published online: January 21, 2023
ARTICLE HIGHLIGHTS
Research background

Metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed in 2020 as the new definition of fatty liver. Compared to nonalcoholic fatty liver disease (NAFLD), MAFLD consists of inclusion criteria characterized by metabolic dysfunction and associated risk factors. There is still a lack of awareness regarding this new MAFLD terminology and its impact on clinical practice.

Research motivation

There have been numerous debates regarding whether the new term MAFLD should be adopted. The definition of MAFLD reflects a shift in the focus from sub typing patients with hepatic steatosis and no discernible cause of fatty liver to the underlying metabolism - related etiology of the disease.

Research objectives

This study summaries existing data that evaluate the long-term outcome differences of the terminology change from NAFLD to MAFLD, classification of hepatic steatosis, histopathological classification, risk factors and pathophysiological mechanisms of the new proposed terminology.

Research methods

A systemic search of database MEDLINE via PubMed and EMBASE were conducted to identify relevant studies up to June 28, 2022.

Research results

Of the 2324 records screened, 1575 duplicates were removed, following which 207 articles were excluded and a remaining 542 articles were assessed for eligibility. 511 articles were excluded and a remaining 31 articles were selected for review. Studies show that MAFLD patients were able to identify more patients with fatty liver compared to NAFLD. MAFLD criteria was also superior or concordant in terms of advanced fibrosis. MAFLD is also associated with higher all-cause mortality, cardiovascular disease - related and cancer - related mortality compared to NAFLD patients.

Research conclusions

MAFLD is gaining acceptance as a new definition of fatty liver disease. The nomenclature and definition of MAFLD highlights the metabolic risk factor which are main drivers of disease progression.

Research perspectives

MAFLD consists of 3 subtypes, each with a unique metabolic dysfunction profile that may be useful for development of new pharmacotherapy. However, further understanding is required to determine the molecular basis of MAFLD as a disease entity and new insights into risk stratification.