COVID-19 and Diabetes

Following the discovery of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China, it has been transmitted to travelers through respiratory droplets and distributed worldwide. Viral, environmental, and host factors all play a role in getting infected with the virus and having severe forms of the disease named coronavirus disease 2019 (COVID-19). Diabetes is one of the most important host risk factors in the progression and severity of COVID-19. In diabetes, hyperglycemia and protein glycosylation increase pro-inflammatory cytokines levels and suppress innate and adaptive immune system by impairing the function of neutrophils, macrophages, and lymphocytes, especially regulatory T lymphocytes. The compromised immune system in diabetic patients makes them vulnerable to infectious diseases like COVID-19. Correspondingly, people with diabetes are usually treated with angiotensin-converting enzyme (ACE) inhibitors and angiotensin II Type-I receptor blockers (ARBs), which increase ACE2 expression as a receptor for SARS-CoV-2. Thus, diabetic patients are more likely to develop severe forms of COVID-19 and die due to chronic inflammation and impaired immune function.