Is elevated blood glucose at admission associated with poor outcomes in hospitalized COVID-19 patients?

Objective: Hyperglycemia has been suggested as a risk factor for poor outcomes in coronavirus disease 2019 (COVID-19). The aim of our work was to evaluate the association between blood glucose levels at admission (BGA) and disease outcomes in hospitalized COVID-19 patients. Subjects and methods: Retrospective study including all adult COVID-19 patients admitted to a Portuguese hospital from March to August 2020 with BGA measurement. Subjects were categorized into two groups: BGA < 140 mg/dL and >= 140 mg/dL. Statistical analysis was performed using SPSSv26 (R) (significance defined as p < 0.05). Results: We included 202 patients: median age 74 (60-86) years; 43.1% female; 31.2% with diabetes. The median BGA was 130.5 (108-158) mg/dL. When compared to normoglycemic, patients with BGA >= 140 mg/dL were older (p = 0.013), more vaccinated for influenza (p = 0.025) and had more comorbidities (hypertension, heart failure and peripheral arterial disease, p < 0.05). The last group presented higher leucocyte and neutrophile count, higher procalcitonin and prothrombin time, and lower lymphocyte count. Concerning prognosis, BGA >= 140 mg/dL was associated with higher rates of mechanical ventilation requirement and intensive care unit admission (p < 0.001), shock (p = 0.011), in-hospital mortality (p = 0.022) and 30-day mortality (p = 0.037). Considering only nondiabetic patients (n = 139), those with hyperglycemia presented higher rates of severity indicators (polypnea, SatO(2) <= 93% and PaO2/FiO(2) = 300) and an association with poor outcomes was also found, namely mechanical ventilation requirement and in-hospital/30-day mortality (p < 0.05). Conclusion: Hyperglycemia at admission was associated with poor outcomes in COVID-19 patients, even in those without known pre-existing diabetes. Glycemic testing should be recommended for all COVID-19 patients.