Clinical characteristics, risk factors, and prognosis of incidental and symptomatic hospital-acquired pulmonary embolism: A retrospective cohort study

Objectives To compare the clinical characteristics, risk factors, and prognosis of incidental pulmonary embolism (IPE) and symptomatic pulmonary embolism (SPE), and to inform risk-stratified management. Methods This retrospective study analyzed 287 patients with hospital-acquired pulmonary embolism (HA-PE). Demographic, clinical, imaging, and laboratory data were collected. Survival outcomes were assessed using Cox regression and Kaplan-Meier analyses. Results Among 287 patients, 87 had IPE and 200 had SPE. IPE was more frequently classified as low-risk PE (63.22% vs. 31.50%, p < 0.001) and more often involved pulmonary artery branches (73.56% vs. 58.00%, p = 0.01), whereas SPE was more commonly intermediate- or high-risk. The 1-month survival rate was higher in the IPE group than in the SPE group (95.4% vs. 75.5%, hazard ratio [HR]: 5.95, 95% confidence interval [CI]: 2.51 - 16.5, p < 0.001), but this difference was not significant after 1 month. In IPE, cancer and bleeding were associated with increased mortality, whereas anticoagulation and lower PE risk categories were associated with reduced mortality. In SPE, cancer and immobilization were associated with increased mortality, whereas anticoagulation, thrombectomy, and lower PE risk categories were associated with reduced mortality. Conclusions IPE is generally associated with lower-risk, more peripheral PE, but anticoagulation should be individualized. SPE requires prompt risk stratification and timely anticoagulation, with reperfusion or thrombectomy considered for selected high-risk or deteriorating patients.