Clinical impact of pulmonary embolism in hospitalized patients with breast cancer: A National Inpatient Sample analysis.

e22623 Background: Pulmonary embolism (PE) is a serious thromboembolic complication in hospitalized patients with malignancy, including breast cancer, yet nationwide data on its inpatient burden and outcomes remain limited. This study aims to determine PE prevalence among hospitalized breast cancer patients and evaluate its associations with comorbidities, inpatient complications, procedures, and clinical outcomes using a nationally representative database. Methods: A retrospective cohort study was conducted using the National Inpatient Sample (NIS), including 982,110 hospitalizations with a diagnosis of breast cancer. Patients were stratified into those with PE and without PE. Baseline demographics, comorbidities, inpatient complications, and procedures were compared. Multivariable logistic regression was used to estimate adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for clinical outcomes, adjusting for demographic and clinical confounders. Results: Pulmonary embolism was identified in 1.5% (n = 14,740) of hospitalized breast cancer patients, while 98.5% (n = 967,370) did not have PE. The cohort was predominantly female (99%) in both groups. Patients with PE had a significantly higher prevalence of medical comorbidities, including hypertension, diabetes, chronic pulmonary disease, obesity, anemia, coagulopathy, and congestive heart failure (all p < 0.001). PE was associated with markedly higher rates of acute inpatient complications, including acute respiratory failure, shock, sepsis, acute kidney injury, and need for mechanical ventilation (all p < 0.001). Patients with PE also demonstrated greater utilization of invasive and critical care–related procedures, including central venous catheterization and thrombolytic or vascular interventions. On multivariable analysis, pulmonary embolism remained independently associated with worse in-hospital outcomes, including increased mortality, prolonged length of stay, higher total hospital charges, and non-routine discharge disposition compared with breast cancer patients without PE. Conclusions: In this large nationwide NIS analysis, pulmonary embolism occurred in a clinically meaningful proportion of hospitalized breast cancer patients and was independently associated with increased morbidity, healthcare utilization, and adverse inpatient outcomes. These findings underscore the importance of heightened risk stratification, early diagnosis, and optimized inpatient management of PE in breast cancer patients.