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

Paolo Fadini, Gian; Luca Morieri, Mario; Boscari, Federico; Fioretto, Paola; Maran, Alberto; Busetto, Luca; Maria Bonora, Benedetta; Selmin, Elisa; Arcidiacono, Gaetano; Pinelli, Silvia; Farnia, Filippo; Falaguasta, Daniele; Russo, Lucia; Voltan, Giacomo; Mazzocut, Sara; Costantini, Giorgia; Ghirardini, Francesca; Tresso, Silvia; Maria Cattelan, Anna; Vianello, Andrea; Avogaro, Angelo; Vettor, Roberto

Abstract 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.