Glycated haemoglobin levels among 3295 hospitalized COVID-19 patients, with and without diabetes, and risk of severe infection, admission to an intensive care unit and all-cause mortality

AimTo determine the risk of adverse outcomes across the spectrum of glycated haemoglobin (HbA1c) levels among hospitalized COVID-19 patients with and without diabetes.Materials and methodsDanish nationwide registries were used to study the association between HbA1c levels and 30-day risk of all-cause mortality and the composite of severe COVID-19 infection, intensive care unit (ICU) admission and all-cause mortality. The study population comprised patients hospitalized with COVID-19 (3 March 2020 to 31 December 2020) with a positive polymerase chain reaction (PCR) test and an available HbA1c ≤ 6 months before the first positive PCR test. All patients had at least 30 days of follow-up. Among patients with diabetes, HbA1c was categorized as 64 mmol/mol. Among patients without diabetes, HbA1c was stratified into ResultsWe identified 3295 hospitalized COVID-19 patients with an available HbA1c (56.2% male, median age 73.9 years), of whom 35.8% had diabetes. The median HbA1c was 54 and 37 mmol/mol among patients with and without diabetes, respectively. Among patients with diabetes, the standardized absolute risk difference of the composite outcome was higher with HbA1c 64 mmol/mol (15.1% [95% CI 6.2% to 24.0%]), compared with HbA1c 59 to 64 mmol/mol (reference). Among patients without diabetes, the standardized absolute risk difference of the composite outcome was greater with HbA1c ConclusionsPatients with COVID-19 and HbA1c 64 mmol/mol had a higher associated risk of the composite outcome. Similarly, among patients without diabetes, varying HbA1c levels were associated with higher risk of the composite outcome.