ABSTRACTObjective:Various studies have shown that diabetes mellitus (DM) increases the risk of thrombosis in the venous system as well as in the arterial system. In this study, it was aimed to evaluate the association between admission blood glucose levels and clinical severity, recurrence, and mortality in pulmonary embolism in patients with DM.Materials and methods:This study was designed as a retrospective cross-sectional study. Patients with DM who were admitted to a tertiary care hospital due to pulmonary embolism (PE) between 2014 and 2019 were included. Demographic characteristics, radiological findings, clinical class of embolism, and mortality data were retrieved from hospital records. Patients with and without recurrent disease, as well as patients who survived and died, were compared. Also, patients were classified according to quartiles of admission blood glucose levels. The quartiles were compared in terms of mortality, clinical, class, and recurrence.Results:Two hundred ninety-three patients with DM and PE were included in the study. Patients with adverse outcome had significantly higher admission blood glucose levels (respectively, 197.9 ± 96.30 mg/dL vs. 170.7 ± 74.26 mg/dL; p = 0.03). Patients in the third and fourth quartile of admission blood glucose levels (>152 mg/dL) had significantly more severe disease with a higher proportion of massive and sub-massive PE and higher pro-BNP levels (respectively, p = 0.01 and 0.02).Conclusion:Non-survived patients and recurrent disease were associated with higher admission blood glucose levels. Also, patients with admission blood glucose levels higher than 152 mg/dL tend to have clinically more severe diseases.