Systematic Reviews
Copyright ©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Mar 27, 2024; 16(3): 452-464
Published online Mar 27, 2024. doi: 10.4254/wjh.v16.i3.452
Update in lean metabolic dysfunction-associated steatotic liver disease
Karina Sato-Espinoza, Perapa Chotiprasidhi, Mariella R Huaman, Javier Díaz-Ferrer
Karina Sato-Espinoza, Perapa Chotiprasidhi, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN 55902, United States
Mariella R Huaman, Obesity and Metabolic, Center for Obesity and Metabolic Health, Lima 02002, Lima, Peru
Javier Díaz-Ferrer, Hepatology Service, Department of Digestive Diseases, Hospital Nacional Edgardo Rebagliati Martins, Lima 02002, Lima, Peru
Javier Díaz-Ferrer, Medicine Faculty, Universidad San Martin de Porres, Lima 02002, Lima, Peru
Javier Díaz-Ferrer, Gastroenterology Service, Clinica Internacional, Lima 02002, Lima, Peru
Author contributions: Sato-Espinoza K, Huaman MR, Diaz-Ferrer J, Chotiprasidhi P performed the methodology, wrote, reviewed and edited the manuscript.
Conflict-of-interest statement: There is no conflict of interest for any of the authors in this manuscript.
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: Karina Sato-Espinoza, MD, Research Fellow, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, 200 First ST SW, Rochester, MN 55902, United States. sato.angela@mayo.edu
Received: December 26, 2023
Peer-review started: December 26, 2023
First decision: January 11, 2024
Revised: January 19, 2024
Accepted: February 28, 2024
Article in press: February 28, 2024
Published online: March 27, 2024
ARTICLE HIGHLIGHTS
Research background

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the new nomenclature of non-alcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD). It is a complex condition, and its mechanism is poorly understood. There are several studies involving overweight/obese patients but there is very limited literature available regarding lean patients.

Research motivation

Only one clinical guideline is available for physicians to diagnosis and manage lean patients with MASLD. However, the pathogenesis, accurate treatment, risk factor and outcomes remain unknown.

Research objectives

The aim of this systematic review is to report literature of diagnosis, pathogenesis, characteristics, and prognosis in lean MASLD patients in diverse populations, and provide an interpretation of the new MASLD criteria.

Research methods

A search on two large databases was conducted, PubMed and Google Scholar, selecting original articles published between January 2012 and September 2023 specifically focusing on lean NAFLD, MAFLD, or MASLD patients.

Research results

85 articles met the eligibility criteria and underwent further analysis. The prevalence of lean MASLD among diverse populations ranges from 4% to 34%. The pathogenesis of lean MASLD involves genetic, epigenetic, and metabolic factors; however, the mechanism remains elusive. Although adequate treatment remains challenging to identify, lifestyle modifications have proven effective in reducing hepatic steatosis and improving cardiometabolic profiles. Some medications have shown efficacy to a lesser extent.

Research conclusions

MASLD is a complex condition that requires attention, especially in lean patients. Risk factors and metabolic conditions are associated with this condition independently of BMI. Therefore, investigations aimed at decreasing the risk of future complications, such as cirrhosis or the development of hepatocellular carcinoma in lean MASLD patient, are necessary with the same relevance as in overweight/obese counterparts.

Research perspectives

Future studies using this new nomenclature of MASLD can contribute to standardizing and generalizing study results in lean patients with steatotic liver diseases. It is also important to take into consideration other values, such as muscle mass or waist circumference and not only BMI, to make a more accurate evaluation of the lean patients.