Abstract
AIMS/INTRODUCTION: To assess the association of undiagnosed diabetes mellitus and its acute-to-chronic glycemic ratio with clinical outcome in patients hospitalized with coronavirus disease 2019 (COVID-19) using a large-scale nationwide registry in Japan. MATERIALS AND METHODS: Overall, 4,747 patients were included between July 2021 and January 2022. We evaluated blood glucose and glycated hemoglobin levels at admission, and calculated the acute-to-chronic glycemic ratio for each non-diabetes mellitus, undiagnosed diabetes mellitus and pre-existing diabetes mellitus group. The primary composite outcome comprised in-hospital mortality, invasive mechanical ventilation, extracorporeal membrane oxygenation support, intensive care unit admission and transfer to a more advanced medical facility. RESULTS: Compared with the non-diabetes mellitus group, the undiagnosed diabetes mellitus group was significantly associated with a worse COVID-19 outcome (odds ratio 2.18, 95% confidence interval 1.50-3.18). In patients with undiagnosed diabetes mellitus, the 3rd tertile of the acute-to-chronic glycemic ratio was linked with a worse COVID-19 outcome compared with the 1st tertile (odds ratio 3.33, 95% confidence interval 1.43-7.77), whereas glycated hemoglobin levels were not; among patients with pre-existing diabetes mellitus, glycated hemoglobin levels were linked with a worse outcome. CONCLUSIONS: Among patients with undiagnosed diabetes mellitus with COVID-19, the magnitude of elevation of blood glucose from chronic to acute levels is associated with worse outcomes.