Diabetes Mellitus and COVID-19

Abstract

The novel coronavirus disease (COVID-19) has scourged the world since its outbreak in December 2019 in Wuhan, China. The disease tends to be asymptomatic or mild in nearly 80% of the patients. However, around 5% of the patients tend to have critical diseases complicated by acute respiratory distress syndrome (ARDS), shock, and multiple organ failure. The disease tends to be specifically severe in patients with advancing age and in those with underlying comorbidities. Diabetes mellitus has emerged as distinctive comorbidity that is associated with severe disease, acute respiratory distress syndrome, intensive care unit admission, and mortality in COVID- 19. The impaired innate immune system, underlying pro-inflammatory milieu, reduced expression of angiotensin-converting enzyme 2 (ACE2), and concomitant use of reninangiotensin- aldosterone system-active drugs are some of the proposed pathophysiological links between diabetes mellitus and COVID-19 severity. On the contrary, the presence of active COVID-19 infection in a patient with underlying diabetes mellitus leads to the worsening of glucose control. Although glucose control prior to hospital admission has not been consistently associated with clinical outcomes in diabetic patients with COVID-19, in-hospital good glycemic control is associated with a lower rate of complications and all-cause mortality.