Background: COVID-19 and dexamethasone predispose patients to hyperglycaemia, an independent risk factor for severity and mortality in COVID-19 patients. Data is scarce on diurnal glycaemic variation in COVID-19 patients on dexamethasone which could provide key insights into best prevention and management of hyperglycaemia in this population.
Methodology: We conducted a retrospective observational study on 144 patients managed with morning 6mg dexamethasone for COVID-19 at St George Hospital between August 2021 and January 2022. We measured blood glucose levels (BGLs) pre-breakfast, pre-lunch, pre-dinner and bedtime. New diabetes was defined as HbA1c >/= 6.5% or >/= 2 separate episodes of BGL >/= 11.1 mmol/L. Patients admitted to intensive care during dexamethasone course were excluded. We did not analyse influence of diabetes treatment on BGLs.
Results: Median age was 60 years and 55% were male. Out of the patients with known/newly diagnosed diabetes, 42/43 had T2DM. Incidence of newly diagnosed diabetes was 27% (27/101). Median BGL profile for patients without diabetes was: 6.3 mmol/L pre-breakfast, 7.4 mmol/L pre-lunch, 8.0 mmol/L pre-dinner and 7.5 mmol/L bedtime. In patients with known or newly diagnosed diabetes, median BGL profile for those with HbA1c <7.0% was: 7.6 mmol/L pre-breakfast, 11.1 mmol/L pre-lunch, 12.6 mmol/L pre-dinner and 11.0 mmol/L bedtime. Median BGL profile for those with HbA1c 7-10% was: 7.7 mmol/L pre-breakfast, 13.0 mmol/L pre-lunch, 14.4 mmol/L pre-dinner and 13.3 mmol/L bedtime. Median BGL profile for those with HbA1c > 10% was: 12.2 mmol/L pre-breakfast, 13.9 mmol/L pre-lunch, 14.4 mmol/L pre-dinner and 13.9 mmol/L bedtime. Peak BGL in all cohorts occurred pre-dinner.
Conclusions: We found baseline glycaemic control impacted severity and duration of hyperglycaemia. Only patients with HbA1c >10% experienced persistent hyperglycaemia overnight. HbA1c may guide expected diurnal glycaemic variation in patients with COVID-19 on dexamethasone, which may inform approaches to glycaemic treatment in these patients.