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World J Diabetes. May 15, 2021; 12(5): 642-650
Published online May 15, 2021. doi: 10.4239/wjd.v12.i5.642
COVID-19 and hyperglycemia/diabetes
Konstantinos Michalakis, Ioannis Ilias
Konstantinos Michalakis, Private Practice, Athens GR-11521, Greece
Ioannis Ilias, Department of Endocrinology, Diabetes and Metabolism, Elena Venizelou Hospital, Athens GR-11521, Greece
Author contributions: Ilias I was the guarantor and planned the review; Ilias I and Michalakis K reviewed the literature and wrote the initial manuscript, conceived and drew the figure; Ilias I and Michalakis K critically revised the article for important intellectual content.
Conflict-of-interest statement: Nothing to declare.
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: Ioannis Ilias, MD, PhD, Consultant Physician-Scientist, Department of Endocrinology, Diabetes and Metabolism, Elena Venizelou Hospital, 2 Elena Venizelou Sq, Athens GR-11521, Greece. iiliasmd@yahoo.com
Received: January 19, 2021
Peer-review started: January 19, 2021
First decision: February 12, 2021
Revised: February 26, 2021
Accepted: April 20, 2021
Article in press: April 20, 2021
Published online: May 15, 2021
Processing time: 106 Days and 23.1 Hours
Abstract

In early studies regarding coronavirus disease 2019 (COVID-19), type 2 diabetes mellitus was considered to contribute substantially to the disease’s inflammatory response. Subsequently, even hyperglycemia, regardless of insulin resistance or diabetes mellitus, was found to be additionally harmful. Recent studies have shown inflammation of the pancreatic β cells in COVID-19, even leading to new onset diabetes mellitus. We hereby summarize core literature on glycemia and COVID-19, and present implicated pathways and mechanisms.

Keywords: COVID-19; Humans; SARS-CoV-2; Risk factors; Glucose; Inflammation; Diabetes

Core Tip: The severe acute respiratory syndrome coronavirus 2 pathogen has led to the coronavirus disease 2019 (COVID-19) pandemic. This virus exerts multi-organ actions after an initial respiratory infection. In early studies regarding COVID-19, type 2 diabetes mellitus was considered to contribute substantially to the disease’s inflammatory response. Hyperglycemia in COVID-19, irrespective of insulin resistance or history of diabetes, is a portent of worse prognosis. Further studies will help elucidate the link between glycemia and COVID-19.