Coronavirus disease-19 (COVID-19) can manifest as fever, cough, and shortness of breath and is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Occasionally, these patients may present with diabetic ketoacidosis (DKA). Patients with comorbidities such as diabetes mellitus and hypertension, as well as older age groups, are known to have a more severe disease progression and poor prognosis. In this review article, we attempt to better understand the disease process in diabetics and also discuss potential mechanisms by which diabetes may play a role in disease severity. This includes the effect of diabetes on the immune response and immune dysregulation. The role of diabetes mellitus in molecular processes including augmenting Angiotensin-Converting Enzyme 2 (ACE 2) levels is also discussed as potential mechanisms to explain the grave prognosis seen in these patients.