Background: Venous thromboembolism (VTE) is a frequent complication in critically ill patients with coronavirus disease 2019 (COVID-19) and is associated with mortality . Early diagnosis and treatment of VTE is warranted .
Objective: To develop a prediction model for VTE in critically ill COVID-19 patients. Patients and methods: In this retrospective cohort study, 127 adult patients with confirmed COVID-19 infection admitted to the intensive care unit of two teaching hospitals were included . VTE was diagnosed with either ultrasound or computed tomography scan.Univariate receiver operating characteristic (ROC) curves were constructed for Positive End Expiratory Pressure, PaO2/FiO2 ratio, platelet count, international normalized ratio, activated partial thromboplastin time as well as levels of fibrinogen, antithrombin, D-dimer and C-reactive protein (CRP). Multivariate analysis was done using binary linear regression .
Results: Variables associated with VTE in both univariate and multivariate analysis were D-dimer and CRP with an area under the curve (AUC) of 0.64, P = 0.023 and 0.75, P = 0.045, respectively . Variables indicating hypoxemia were not predictive . The ROC curve of D-dimer and CRP combined had an AUC of 0.83, P <0.05 . Categorized values of D-dimer and CRP were used to compute a mean absolute risk for the combination of these variables with a high positive predictive value . The predicted probability of VTE with a D-dimer> 15 in combination with a CRP> 280 was 98% . The negative predictive value of D-dimer was low . Conclusion: Elevated CRP and D-dimer have a high positive predictive value for VTE in critically ill COVID-19 patients. We developed a prediction table with these biomarkers that can aid clinicians in the timing of imaging in patients with suspected VTE.