Abstract
Background
Pulmonary embolism (PE) may be difficult to detect in patients with severe community-acquired pneumonia (SCAP) because symptoms and physiological abnormalities overlap with those of severe infection and respiratory failure. Early identification of patients at high risk of PE may facilitate timely diagnostic evaluation. This study aimed to identify factors associated with PE among patients with SCAP admitted to the intensive care unit (ICU) and to establish and validate a nomogram for identifying those at high risk of PE.
Methods
Clinical data from 3148 ICU patients with SCAP were retrospectively analyzed using the Medical Information Mart for Intensive Care IV (MIMIC-IV, version 2.2; 2008–2019) database. A random 7:3 split was used to form the training cohort (n = 2204) and validation cohort (n = 944). Independent predictors were determined by least absolute shrinkage and selection operator followed by multivariable logistic regression, and these predictors were used to build a nomogram. The model was assessed in terms of discrimination, calibration, and clinical net benefit using the area under the receiver operating characteristic curve (AUROC), calibration curves and Brier scores, and decision curve analysis (DCA), respectively.
Results
Among the 3148 ICU patients with SCAP, PE was identified in 152 patients (4.83%). Age, sex, heart rate, creatinine, prothrombin time, activated partial thromboplastin time, and partial pressure of oxygen were independently associated with PE in patients with SCAP. The model achieved AUROC values of 0.683 (95% CI, 0.635–0.731) in the training cohort and 0.658 (95% CI, 0.567–0.749) in the validation cohort. The Brier scores were 0.0464 and 0.0416 in the training and validation cohorts, respectively, and the calibration curves showed good consistency between predicted and observed risks. Bootstrap internal validation with 1000 resamples yielded an optimism-corrected AUROC of 0.661. DCA indicated a clinical net benefit for threshold probabilities of approximately 0.03–0.15.
Conclusions
This study constructed the first model for estimating PE risk among ICU patients with SCAP and validated its performance. The model demonstrated modest discrimination and good calibration and may facilitate early PE risk assessment and stratification in this population. However, its predictive performance and clinical applicability require further validation in independent external cohorts.
Trial registration
Not applicable. This study is a retrospective observational analysis based on the MIMIC-IV database.
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Abbreviations
- SCAP:
-
Severe community-acquired pneumonia
- PE:
-
Pulmonary embolism
- ICU:
-
Intensive care unit
- MIMIC-IV:
-
Medical Information Mart for Intensive Care IV
- AUROC:
-
Area under the receiver operating characteristic curve
- DCA:
-
Decision curve analysis
- CAP:
-
Community-acquired pneumonia
- VTE:
-
Venous thromboembolism
- DVT:
-
Deep vein thrombosis
- COVID-19:
-
Coronavirus disease 2019
- BIDMC:
-
Beth Israel Deaconess Medical Center
- IRB:
-
Institutional Review Board
- ICD-CM:
-
International Classification of Diseases, Clinical Modification
- ICU-LOS:
-
ICU length of stay
- Hospital-LOS:
-
Hospital length of stay
- SBP:
-
Systolic blood pressure
- DBP:
-
Diastolic blood pressure
- MAP:
-
Mean arterial pressure
- SpO2 :
-
Peripheral oxygen saturation
- BUN:
-
Blood urea nitrogen
- UCR:
-
Urea nitrogen to creatinine ratio
- WBC:
-
White blood cell count
- PLT:
-
Platelet count
- CRP:
-
C-reactive protein
- INR:
-
International normalized ratio
- PT:
-
Prothrombin time
- APTT:
-
Activated partial thromboplastin time
- Lac:
-
Lactate
- HCO₃⁻:
-
Bicarbonate
- PCO2 :
-
Partial pressure of carbon dioxide
- PO2 :
-
Partial pressure of oxygen
- CHF:
-
Congestive heart failure
- SIRS:
-
Systemic Inflammatory Response Syndrome Score
- SAPS II:
-
Simplified Acute Physiological Score II
- GCS:
-
Glasgow Coma Scale
- SOFA:
-
Sequential Organ Failure Assessment Score
- IQR:
-
Interquartile range
- LASSO:
-
Least absolute shrinkage and selection operator
- λ:
-
Lambda
- AIC:
-
Akaike information criterion
- ORs:
-
Odds ratios
- CIs:
-
Confidence intervals
- RCS:
-
Restricted cubic spline
- VIF:
-
Variance inflation factor
- MSEP:
-
Mean squared error for the probability of a binary outcome
- CTPA:
-
Computed tomography pulmonary angiography
Acknowledgements
The authors sincerely thank all contributors involved in the development and maintenance of the MIMIC-IV database for their valuable efforts and support.
Funding
This study was supported by grants from the National Natural Science Foundation of China (82560078 and 82660019), Yunnan Province’s Xingdian Talent Support Program Medical and Health Talents Special Project (No. XDYC-YLWS-2023-0043), Yunnan Province’s Xingdian Talent Support Program Special Project for Young Talents (No. XDYC-QNRC-2025-078), Yunnan Provincial Innovation Team for Respiratory and Pulmonary Circulation Diseases (No. 202405AS350018), the Yunnan Fundamental Research Projects (202501CF070056 and 202601BF070001-057), Yunnan University Fund for Medical Research (No. YDYXJJ2024-0034), and Yunnan Major Science and Technological Project (No. 202502AA310030).
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All patient information in the database was fully de-identified, and the establishment of the MIMIC-IV database had been approved by the IRB of BIDMC (No. 2001P001699). Therefore, additional ethical review for the present study was not required.
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Zeng, B., Wu, J., Liu, T. et al. Development and validation of a risk prediction model for severe community-acquired pneumonia associated pulmonary embolism. BMC Pulm Med (2026). https://doi.org/10.1186/s12890-026-04878-9
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DOI: https://doi.org/10.1186/s12890-026-04878-9