The Impact of Deranged Glucose Metabolism and Diabetes in the Pathogenesis and Prognosis of the Novel SARS-CoV-2: A Systematic Review of Literature

Background: The novel coronavirus disease (COVID-19), declared a global pandemic by the World Health Organization (WHO) on March 11, 2020, and has constituted one of the most serious health challenges of the century, globally. The causative organism was initially named the 2019 novel coronavirus (2019 n CoV) but has subsequently been renamed Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The pandemic has so far infected several millions and killed about a million people worldwide. Diabetes mellitus (DM) is one of the leading causes of morbidity worldwide. Objectives: To examine the critical role diabetes plays in the pathogenesis and prognosis of COVID-19 and to assess the emerging therapies available to fight the pandemic. Methods: Authors conducted a systematic review of the literature to examine the role of diabetes as comorbidity in the pathogenesis and prognosis of COVID-19 by searching PubMed and Science Direct databases mainly for articles published since the outbreak of the pandemic. Results: Both experimental and observational data from early 2020 suggested that most people with COVID-19 have comorbidities, the most dominant of which are diabetes, cardiovascular disease, and hypertension. Empirical evidence indicates that diabetic patients infected with the COVID-19 disease had the worst outcomes concerning morbidity and mortality. Conclusion: A combination of underlying chronic conditions such as hypertension, obesity, and cardiovascular diseases together with altered ACE receptor expression, immune dysregulation via cytokine storm, alveolar and endothelial dysfunction, increased systemic coagulation may put individuals with diabetes at risk for COVID-19 severity. More studies are needed to elucidate how glucose- lowering drugs may modulate the host immune response in diabetic individuals, especially following the administration of potential COVID-19 vaccines.