There are three aspects that can affect the patient’s glycaemic control during infection with COVID-19:

1. COVID-19 infection impairs insulin production from the pancreatic beta cells
2. COVID-19 infection can also cause insulin resistance
3. Dexamethasone impairs glucose metabolism

The effect of these three factors can cause significant hyperglycaemia, hyperglycaemic hyperosmolar syndrome (HHS) and diabetic ketoacidosis (DKA) in people with and without diabetes, increasing both morbidity and mortality, so good glucose control is vital in these patients. 

A guideline has been put together to help in the management of steroid-induced hyperglycaemia in patients admitted with COVID-19 who are on Dexamethasone (linked below).

Key points from the guideline:

• Patients should be grouped into those with pre-existing diabetes and no history of diabetes
• If a patient has pre-existing diabetes, Metformin and any SGLT2 inhibitors should be stopped for the duration of the steroid treatment
• Regular monitoring of blood glucose should start as soon as dexamethasone is initiated
• The cut-off for hyperglycaemia is a blood glucose more than 12mmol/L
• If a patient is hyperglycaemic, the guideline outlines the interventions most appropriate for the patient using a sequence of tables
• The guideline also outlines a strategy for withdrawing insulin therapy once the dexamethasone is stopped

Once the Dexamethasone has been stopped, patients should have their blood glucose monitored carefully and down-titration of their insulin is recommended. It is unlikely that patients who had no previous diagnosis of diabetes will need insulin when they are discharged, but some may need insulin for short periods of time.