What does this research mean for the field?

Machine learning models improve in-hospital mortality prediction for pulmonary embolism in non-COVID patients compared to PESI, but their performance declines in COVID-19 patients. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This research aims to enhance early risk stratification for mortality in pulmonary embolism patients, particularly those with COVID-19.

February 25, 2026Open Access

Predicting Mortality in Pulmonary Embolism: A Machine Learning Approach with External Validation in COVID-19 Patients

Key Points

This research aims to enhance early risk stratification for mortality in pulmonary embolism patients, particularly those with COVID-19.
Conducted a retrospective study with 538 patients admitted for acute pulmonary embolism.
Employed univariate analysis and machine learning models to evaluate mortality risk.
Compared the performance of machine learning models with the PESI prognostic tool.
Mortality risk was significantly associated with sepsis and PESI class V in univariate analysis.
In non-COVID patients, machine learning models like XGBoost performed better than PESI (AUC 0.864 vs. 0.725).
In COVID-19 patients, the performance of these models decreased significantly, indicating a need for model refinement.

Abstract

Background and Objectives: Pulmonary embolism (PE) is a frequent thrombotic complication associated with SARS-CoV-2 infection and is linked to significant early mortality. Accurate early risk stratification in the emergency department (ED) remains challenging, and it is unclear how well commonly used PE prognostic tools perform in patients with concomitant COVID-19. Materials and Methods: We conducted a retrospective, single-centre study including 538 consecutive patients with acute PE and with or without confirmed SARS-CoV-2 infection admitted through the ED. Univariate analysis and machine learning models were employed to assess mortality risk. Results: In univariate analysis, mortality was strongly associated with sepsis (OR 11.68) and PESI class V (OR 5.56) and was also linked to higher neutrophil count (OR 1.19), platelet count (OR 1.12), and NT-proBNP (OR 1.20). In the non-COVID cohort, XGBoost and RF showed better discrimination than PESI class (AUC 0.864 and 0.834 vs. 0.725), while Support Vector Machines (SVM) was lower (AUC 0.740). On COVID-19 external validation, discrimination decreased: XGBoost AUC was 0.635, RF 0.614, PESI 0.584, and SVM showed no discrimination. Conclusions: ML models using routinely available ED variables improved in-hospital mortality prediction compared with PESI in non-COVID PE, but performance declined in COVID-19 patients, suggesting limited generalizability and the need for COVID-specific refinement and prospective multicenter validation.

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