Heterogeneity in presentation of hyperglycaemia during COVID-19 pandemic: A proposed classification.

Diabetes and hyperglycemia occurring during COVID-19 era have implications for COVID-19 related morbidity/mortality. In this brief review, we have attempted to categorise and classify such heterogenous hyperglycemic states. During COVID-19 pandemic broadly two types of hyperglycemia were seen: one in patients without COVID-19 infection and second in patients with COVID-19 infection. Patients not inflicted with COVID-19 infection and diagnosed with either type 2 diabetes mellitus (T2DM) or type 1 diabetes mellitus (T1DM) show more severe hyperglycemia and more ketoacidosis, respectively. In former, it could be attributed to weight gain, decreased exercise, stress and in both type of diabetes, due to delayed diagnosis during lockdown and pandemic. In patients with COVID-19 and associated pneumonia, altered glucose metabolism leading to hyperglycemia could be due to corticosteroids, cytokine storm, damage to pancreatic beta cells, or combination of these factors. Some of these patients present with diabetic ketoacidosis, hyperglycemic hyperosmolar state or both. We have provided a framework for categorisation of hyperglycemic states, which could be consolidated/revised in future based on new research data.