Clinical and morphological characteristics of newly diagnosed diabetes mellitus in elderly patients with COVID-19

Background: This study examined the pathomorphological changes in the pancreatic islet tissue and their association with glucose metabolism disorders and clinical and laboratory markers of COVID-19 severity in elderly patients. Materials and methods: In a pilot study, 11 elderly patients (mean age: 67.9 ± 4.2 years; 7 men, 4 women) with COVID-19 who had a fatal outcome between 2021 and 2022 were analyzed. Based on clinical diagnosis, the patients were categorized into three groups: group 1, three patients with newly diagnosed diabetes mellitus (DM) associated with COVID-19; group 2, three patients with preexisting type 2 DM and COVID-19; and group 3 (control group), five patients with COVID-19 and no glucose metabolism disorders. Group 1 manifested the smallest pancreatic islet volume. Results: Across the cohort, islet size showed a significant negative correlation with blood glucose levels and a positive correlation with platelet count and total bilirubin (within physiological limits) and antiplatelet therapy use. Moreover, the patients in group 1 exhibited the highest systemic inflammatory activity, higher fasting blood glucose levels, the lowest platelet count, the most pronounced pancreatic lipomatosis and fibrosis, the highest Charlson Comorbidity Index, and the longest hospital stay. Furthermore, preexisting pancreatic morphological changes were found in these patients prior to COVID-19 infection. The patients in group 2 showed the most pronounced bone marrow suppression, which affected peripheral blood cell composition and was possibly associated with a worse prognosis and the shortest time to fatal outcome. Conclusions: These indicate that pancreatic islet damage in COVID-19 is related to the development of DM and occurs in the presence of preexisting pancreatic abnormalities, including lipomatosis and fibrosis.