Newly-diagnosed diabetes and admission hyperglycemia predict COVID-19 severity by aggravating respiratory deterioration

Aims We investigated whether pre-existing diabetes, newly-diagnosed diabetes, and admission hyperglycemia were associated with COVID-19 severity independently from confounders Methods We retrospectively analyzed data on patients with COVID-19 hospitalized between February and April 2020 in an outbreak hospital in North-East Italy Pre-existing diabetes was defined by self-reported history, electronic medical records, or ongoing medications Newly-diagnosed diabetes was defined by HbA1c and fasting glucose The primary outcome was a composite of ICU admission or death Results 413 subjects were included, 107 of whom (25 6%) had diabetes, including 21 newly-diagnosed Patients with diabetes were older and had greater comorbidity burden The primary outcome occurred in 37 4% of patients with diabetes compared to 20 3% in those without (RR 1 85;95%C I 1 33-2 57;p<0 001) The association was stronger for newly-diagnosed compared to pre-existing diabetes (RR 3 06 vs 1 55;p=0 004) Higher glucose level at admission was associated with COVID-19 severity, with a stronger association among patients without as compared to those with pre-existing diabetes (interaction p<0 001) Admission glucose was correlated with most clinical severity indexes and its association with adverse outcome was mostly mediated by a worse respiratory function Conclusion Newly-diagnosed diabetes and admission hyperglycemia are powerful predictors of COVID-19 severity due to rapid respiratory deterioration