Pre-Existing Diabetes and COVID-Associated Hyperglycaemia in Patients with COVID-19 Pneumonia

Simple Summary COVID-associated hyperglycaemia is emerging as a complication of Sars-CoV-2 infection, and this clinical entity still needs to be adequately characterized in comparison to pre-existing diabetes. Few studies have comparatively characterized these two conditions in relation to the presence of comorbidities, pre-hospitalization treatments, symptoms at admission, and laboratory variables associated with COVID-19 severity. Our study generated several interesting findings. Patients with COVID-associated hyperglycaemia had significantly less comorbidities, increased levels of inflammatory markers, and indicators of multi-organ injury than those with pre-existing diabetes, while islet autoimmunity prevalence and anti-SARS-CoV-2 antibody responses were similar. COVID-associated hyperglycaemia was associated with a poorer clinical outcome and a longer viral clearance time compared to pre-existing diabetes. This strongly supports the need to screen all COVID-19 patients for hyperglycaemia at the time of admission despite a mute personal or family history of diabetes and to treat them in order to reach and maintain good glycemic control during hospitalization for COVID-19 pneumonia. Aim. The aim of the current study was to compare clinical characteristics, laboratory findings, and major outcomes of patients hospitalized for COVID-19 pneumonia with COVID-associated hyperglycaemia or pre-existing diabetes. Methods. A cohort of 176 adult patients with a diagnosis of pre-existing diabetes (n = 112) or COVID-associated hyperglycaemia (n = 55) was studied. Results. Patients with COVID-associated hyperglycaemia had lower BMI, significantly less comorbidities, and higher levels of inflammatory markers and indicators of multi-organ injury than those with pre-existing diabetes. No differences between pre-existing diabetes and COVID-associated hyperglycaemia were evident for symptoms at admission, the humoral response against SARS-CoV-2, or autoantibodies to glutamic acid decarboxylase or interferon alpha-4. COVID-associated hyperglycaemia was independently associated with the risk of adverse clinical outcome, which was defined as ICU admission or death (HR 2.11, 95% CI 1.34-3.31; p = 0.001), even after adjustment for age, sex, and other selected variables associated with COVID-19 severity. Furthermore, at the same time, we documented a negative association (HR 0.661, 95% CI 0.43-1.02; p = 0.063) between COVID-associated hyperglycaemia to swab negativization. Conclusions. Recognizing hyperglycaemia as a specific clinical entity associated with COVID-19 pneumonia is relevant for early and appropriate patient management and close monitoring for the progression of disease severity.