Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Oct 6, 2021; 9(28): 8327-8339
Published online Oct 6, 2021. doi: 10.12998/wjcc.v9.i28.8327
Diabetes mellitus and COVID-19: Understanding the association in light of current evidence
Saikat Sen, Raja Chakraborty, Pratap Kalita, Manash Pratim Pathak
Saikat Sen, Manash Pratim Pathak, Faculty of Pharmaceutical Science, Assam down town University, Guwahati 781026, Assam, India
Raja Chakraborty, Department of Pharmaceutical Technology, School of Medical Sciences, ADAMAS University, Kolkata 700 126, West Bengal, India
Pratap Kalita, Department of Pharmacy, Pratiksha Institute of Pharmaceutical Sciences, Guwahati 781026, Assam, India
Author contributions: Sen S designed the study; Sen S, Chakraborty R, Kalita P and Pathak MP carried out the literature search; S Sen, Kalita P and Pathak MP extracted the data from available literature; S Sen, Chakraborty R, Kalita P and Pathak MP were involved in drafting of the manuscript; S Sen and Chakraborty R provided further editing and comments.
Conflict-of-interest statement: Authors declare no conflict of interests for this article.
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:
Corresponding author: Saikat Sen, PhD, Professor, Faculty of Pharmaceutical Science, Assam down town University, Panikhaiti, Guwahati 781026, Assam, India.
Received: March 6, 2021
Peer-review started: March 6, 2021
First decision: March 30, 2021
Revised: April 12, 2021
Accepted: July 29, 2021
Article in press: July 29, 2021
Published online: October 6, 2021

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have posed a problematic healthcare situation worldwide since December 2019. Diabetes mellitus is associated with an increased risk and severity of coronavirus disease 2019 (COVID-19). While interacting with various other risk factors, high blood sugar was found to reduce immunity and increase the replication of SARS-CoV-2. Oxidative stress and the release of pro-inflammatory cytokines are greater in diabetic individuals than in healthy people, worsening the outcome of SARS-CoV-2 infection in diabetics. Increased expression of furin and angiotensin converting enzyme 2 (ACE-2) receptor in the hyperglycemic environment may promote the entry of SARS-CoV-2 in the host cell. COVID-19 infection primarily modulates immune and inflammatory responses, and may cause a cytokine storm, resulting in possible lethal outcomes in diabetics. An experimental report suggests that ACE expressed in the pancreas and the SARS-CoV-2 virus invariably destroy β-cells which contain ACE-2 receptors and results in acute diabetes. Moreover, COVID-19 also causes hyperglycemia in an individual with diabetes which may be related to insulin resistance and destruction of β-cells during SARS-CoV-2 infection. Early observations also suggest a correlation between oral hypoglycemic agents and the risk of COVID-19. This review focused on the possible cause and mechanism involved in SARS-CoV-2 infection in diabetics and the role of antidiabetic drugs in COVID-19.

Keywords: Diabetes mellitus, SARS-CoV-2, COVID-19, Angiotensin converting enzyme 2, Antidiabetic drug, Cytokine storm

Core Tip: This review highlights the significant correlation between diabetes mellitus and coronavirus disease 2019 (COVID-19) in light of available published information. COVID-19 is responsible for increased risk and disease severity in diabetic patients. Cytokine storm, destruction of beta cells and the expression of angiotensin converting enzyme 2 are some of the fundamental mechanisms discussed. This review also summarizes the range of investigations that have been undertaken across a large set of published papers on COVID-19 and diabetes mellitus.