Oxygen saturation and mortality for acute pulmonary embolism: multinational retrospective cohort study

Background Among patients with acute pulmonary embolism ( PE ), we aimed to evaluate for an association between oxygen saturation ( SatO 2 ) and 30-day post-PE mortality. Methods Between January, 2001 and April, 2025, we conducted a retrospective cohort study of 38,739 non-hypotensive patients with acute PE enrolled from 18 countries in the Registro Informatizado de la Enfermedad Tromboembólica ( RIETE ) registry. Outcomes included 30-day all-cause and PE-specific mortality. We used hierarchical logistic regression to assess for an association between baseline SatO 2 and outcomes. We aimed to identify optimal SatO 2 cut-off points that maximized sensitivity and specificity in relation to mortality from receiver operating characteristic ( ROC ) curves. RIETE is registered with ClinicalTrials.gov, NCT02832245. Findings Baseline SatO 2 was significantly associated with mortality, where lower SatO 2 had worse outcomes. Using a reference SatO 2 of >96%, patients in the lower SatO 2 strata had higher rates of all-cause death (odds ratio [ OR ] 0.96 for SatO 2 94–96%; 1.23 for SatO 2 90–93%; and 1.81 for SatO 2