Supplementary Material for: Clinical Relevance of Pleural Effusion in Patients with Pulmonary Embolism

<b><i>Background:</i></b> Data regarding pleural effusion due to pulmonary embolism (PE) are limited. <b><i>Objectives:</i></b> The aim of this study was to investigate the clinical characteristics of PE patients with pleural effusion caused by PE. <b><i>Methods:</i></b> Patients with PE were retrospectively analyzed and divided into 2 groups based on computed tomography: a group with pleural effusion due to PE (effusion group) and a group without pleural effusion (control group). Clinical characteristics were compared between the 2 groups. <b><i>Results:</i></b> The study population consisted of the effusion group (<i>n</i> = 127) and the control group (<i>n</i> = 651). Serum C-reactive protein (CRP) level was significantly higher in the effusion group than in the control group. The percentages of high-risk Simplified PE Severity Index (57 vs. 47%, <i>p</i> = 0.008), central PE (84 vs. 73%, <i>p</i> = 0.013), right ventricular dilation (45 vs. 36%, <i>p</i> = 0.053), and pulmonary infarction (40 vs. 8%, <i>p</i> &lt; 0.001) were higher in the effusion group than in the control group. Multivariate analysis demonstrated that pulmonary infarction (odds ratio [OR] 6.20, 95% confidence interval [CI] 3.49-10.91, <i>p</i> &lt; 0.001) and CRP level (OR 1.05, 95% CI 1.101-1.09, <i>p</i> = 0.023) were independent predictors of pleural effusion due to PE. The presence of pleural effusion was not a predictor of short-term outcomes or length of hospital stay. <b><i>Conclusions:</i></b> Patients with more severe PE are likely to have pleural effusion caused by PE. However, pleural effusion was not a proven predictor of short-term outcome or length of hospital stay. Pulmonary infarction and CRP levels were independent risk factors for the development of pleural effusion.