Late Breaking Abstract - Prevalence of pulmonary embolism among ILD patients with respiratory worsening

<bold>Introduction:</bold> Interstitial lung diseases (ILDs) are a spectrum of disorders, with some individuals undergoing a gradual decline in lung function, while others may suffer from acute exacerbation. Pulmonary embolism (PE) is a potential trigger for respiratory worsening in ILD patients, yet its prevalence in acute settings is unknown. <bold>Objective:</bold> Assessing the prevalence of PE and its risk factors in patients with ILD presenting with acute respiratory worsening. <bold>Methods:</bold> This retrospective cohort study investigated the prevalence and risk factors for PE among all ILD patients hospitalized at the Tel Aviv Medical Center between 2017 and 2023 due to respiratory worsening, and who underwent CT angiography (CTA) within the first 72 hours of admission. <bold>Results:</bold> Among 77 ILD patients enrolled in the study, 18.1% (14) were diagnosed with PE. There was no significant difference in the prevalence of PE across different ILDs. Additionally, there was no notable distinction in survival rates or 30-day mortality between patients with or without PE. Factors such as demographics, active malignancy, vital signs, PFTs, and laboratory values were not significantly different between the PE+ and PE- groups. However, the prevalence of PE was notably higher in ILD patients who had never smoked compared to former or active smokers (30.5% vs. 7.5%, respectively, with an odds ratio of 5.43 and a 95% CI of 1.3-21.4). <bold>Conclusion:</bold> Nearly one in five ILD patients presenting with acute respiratory worsening were diagnosed with PE. Therefore, we suggest that CTA should be used liberally in these settings. The risk of PE rises in never-smokers; this may be due to smokers having respiratory exacerbations from other reasons, such as COPD.