Pulmonary Embolism in Hospitalized COVID-19 Patients: Incidence, Clinical Predictors, and Short-Term Outcomes

Background/Objectives: Pulmonary embolism (PE) represents a major thrombotic complication in hospitalized patients with coronavirus disease 2019 (COVID-19), yet data on its incidence, clinical predictors, and short-term outcomes in actual cohorts remain heterogeneous. Methods: We conducted a retrospective observational cohort study including 395 consecutive adults hospitalized with RT-PCR-confirmed COVID-19 at a tertiary infectious diseases center between March 2020 and December 2024. Clinical, laboratory, imaging, and treatment data were extracted from electronic records, and PE was defined by computed tomography pulmonary angiography. Univariable and multivariable logistic regression analyses were used to identify independent predictors of PE in the subset of patients who underwent CTPA (n = 120), in whom PE status was definitively ascertained (47 with PE and 73 without PE). Results: Pulmonary embolism was diagnosed in 47 patients (11.9%). Patients with PE more frequently had prior venous thromboembolism (19.1% vs. 8.3%) and prolonged immobilization (61.7% vs. 23.0%), and were more often admitted to the intensive care unit (12.8% vs. 4.3%) than those without PE. Peak D-dimer levels were almost ten-fold higher in the PE group (median 5322 vs. 529.5 µg/L). In multivariable logistic regression, peak D-dimer was independently associated with PE (per log-unit increase, adjusted OR 3.9, 95% CI 2.1-7.1), and prolonged immobilization conferred a substantially higher risk of PE (adjusted OR 5.1, 95% CI 2.4-10.9). Patients with PE experienced more complex hospital courses and more frequent need for advanced therapies, although in-hospital mortality did not differ significantly between groups. Conclusions: In hospitalized COVID-19 patients, PE is frequent and closely linked to marked D-dimer elevation and acquired in-hospital risk factors, particularly prolonged immobilization. This evidence supports the use of dynamic D-dimer assessment and careful evaluation of immobilization status to improve risk stratification, guide decisions on diagnostic imaging and anticoagulation intensity, and identify patients who may benefit from closer post-discharge cardiovascular follow-up (this hypothesis requires confirmation in future prospective studies).