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World J Gastroenterol. Apr 28, 2021; 27(16): 1738-1750
Published online Apr 28, 2021. doi: 10.3748/wjg.v27.i16.1738
Coronavirus disease 2019 severity in obesity: Metabolic dysfunction-associated fatty liver disease in the spotlight
Isabela Macedo Lopes Vasques-Monteiro, Vanessa Souza-Mello
Isabela Macedo Lopes Vasques-Monteiro, Vanessa Souza-Mello, Anatomy, Rio de Janeiro State University, Rio de Janeiro 20551030, Brazil
Isabela Macedo Lopes Vasques-Monteiro, Food Science and Technology, Federal University of the State of Rio de Janeiro, Rio de Janeiro 22290250, Brazil
Vanessa Souza-Mello, Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, Anatomy Department, Rio de Janeiro State University, Rio de Janeiro 20551030, Brazil
Author contributions: Souza-Mello V conceived the idea for the manuscript; Vasques-Monteiro IML and Souza-Mello V performed the literature search and data analysis and drafted the manuscript; Vasquez-Monteiro IML designed the figures; Souza-Mello V critically revised the work; all authors read and approved the final version of the manuscript.
Supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brazil), No. 305867/2017-2; and Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, No. E-26/202.657/2018.
Conflict-of-interest statement: The authors have nothing to disclose.
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: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Vanessa Souza-Mello, PhD, Associate Professor, Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, Anatomy Department, Rio de Janeiro State University, Blvd. 28 de setembro 87, Rio de Janeiro 20551030, Brazil. souzamello.uerj@gmail.com
Received: January 10, 2021
Peer-review started: January 10, 2021
First decision: February 11, 2021
Revised: February 15, 2021
Accepted: March 22, 2021
Article in press: March 22, 2021
Published online: April 28, 2021
Abstract

The coronavirus disease 2019 (COVID-19) outbreak has drawn the scientific community's attention to pre-existing metabolic conditions that could aggravate the infection, causing extended viral shedding, prolonged hospitalization, and high death rates. Metabolic dysfunction-associated fatty liver disease (MAFLD) emerges as a surrogate for COVID-19 severity due to the constellation of metabolic alterations it entails. This review outlines the impact MAFLD exerts on COVID-19 severity in obese subjects, besides the possible mechanistic links to the poor outcomes. The data collected showed that MAFLD patients had poorer COVID-19 outcomes than non-MAFLD obese subjects. MAFLD is generally accompanied by impaired glycemic control and systemic arterial hypertension, both of which can decompensate during the COVID-19 clinical course. Also, MAFLD subjects had higher plasma inflammatory marker concentrations than non-MAFLD subjects, which might be related to an intensified cytokine storm syndrome frequently associated with the need for mechanical ventilation and death. In conclusion, MAFLD represents a higher risk than obesity for COVID-19 severity, resulting in poor outcomes and even progression to non-alcoholic steatohepatitis. Hepatologists should include MAFLD subjects in the high-risk group, intensify preventive measurements, and prioritize their vaccination.

Keywords: Metabolic dysfunction-associated fatty liver disease, Obesity, COVID-19, Severity, Cytokine storm syndrome

Core Tip: It is notorious that obesity represents a risk for coronavirus disease 2019 (COVID-19) severity. However, COVID-19 often causes liver alterations or provokes the progression of pre-existing liver diseases. This review outlines the role of metabolic dysfunction-associated fatty liver disease in COVID-19 severity. The evidence available thus far supports the notion that metabolic dysfunction-associated fatty liver disease represents a more intense risk than obesity for hospitalization, extended viral shedding, and death. A pro-inflammatory state with inflammasome activation, implying increased susceptibility to cytokine storm syndrome, underlies these findings and emerges as, in addition to massive vaccination of subjects with liver diseases, potential targets for therapeutic strategies.