COVID-19 pneumonia in patients with impaired fasting glucose, newly diagnosed diabetes and pre-existing diabetes: a tertiary center experience.

COVID-19 infection is known to increase mortality in patients with diabetes. We aim to demonstrate the differences in disease course and clinical outcomes of patients with COVID-19 regarding the presence of impaired fasting glucose, pre-existing diabetes mellitus (DM) or new-onset DM. 236 patients with positive reverse transcription-PCR tests for SARS-CoV-2 were included in this single-center, retrospective observational study between March 2020 and May 2021. Laboratory results, comorbidities, medications and imaging findings were noted. Logistic regression was used to estimate associated factors for admission to the intensive care unit (ICU). 43 patients with normal glucose, 53 with impaired fasting glucose, 60 with newly diagnosed DM, and 80 with pre-existing DM were classified. Patients with pre-existing DM had higher fasting glucose and glycated hemoglobin than the other groups (p<0.001 for all). Patients with newly diagnosed DM were more likely to need dexamethasone 6 mg (p=0.001). In both newly diagnosed diabetes and impaired fasting glucose groups, 250 mg methylprednisolone was needed at higher rates (p=0.002). Newly diagnosed DM had higher rates of intubation (21.6%) and more mortality (20.0%) (p=0.045 and p=0.028, respectively). Mortality and hospitalization in the ICU were lower in the group receiving antidiabetic treatment. The risk of ICU attendance was higher in patients with impaired fasting glucose (HR=1.71, 95% CI: 0.48 to 6.08) and newly diagnosed DM (HR=1.88, 95% CI: 0.57 to 6.17), compared with pre-existing DM and non-diabetics. Newly diagnosed DM and impaired fasting glucose are associated with increased mortality and intubation in inpatients with COVID-19.