Prognostic Value of Venous Thromboembolism Risk Assessment Models in Patients with Severe COVID-19

Introduction  Severe novel corona virus disease 2019 (COVID-19) causes dysregulation of the coagulation system with arterial and venous thromboembolism (VTE). We hypothesize that validated VTE risk scores would have prognostic ability in this population. Methods  Retrospective observational cohort with severe COVID-19 performed in NorthShore University Health System. Patients were >18 years of age and met criteria for inpatient or intensive care unit (ICU) care. The International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) and Caprini scores were calculated and patients were stratified. Results  This study includes 184 patients, mostly men (63.6%), Caucasian (54.3%), 63 years old (interquartile range [IQR]: 24-101), and 57.1% of them required ICU care. Twenty-seven (14.7%) thrombotic events occurred: 12 (6.5%) cases of disseminated intravascular coagulation (DIC), 9 (4.9%) of pulmonary embolism, 5 (2.7%) of deep vein thrombosis, and 1 (0.5%) stroke. Among them, 86 patients (46.7%) died, 95 (51.6%) were discharged, and 3 (1.6%) were still hospitalized. "Moderate risk for VTE" and "High risk for VTE" by IMPROVE score had significant mortality association: (hazard ratio [HR]: 5.68; 95% confidence interval [CI]: 2.93-11.03; p  < 0.001) and (HR = 6.22; 95% CI: 3.04-12.71; p  < 0.001), respectively, with 87% sensitivity and 63% specificity (area under the curve [AUC] = 0.752, p  < 0.001). "High Risk for VTE" by Caprini score had significant mortality association (HR = 17.6; 95% CI: 5.56-55.96; p  < 0.001) with 96% sensitivity and 55% specificity (AUC = 0.843, p  < 0.001). Both scores were associated with thrombotic events when classified as "High risk for VTE" by IMPROVE (HR = 6.50; 95% CI: 2.72-15.53; p  < 0.001) and Caprini scores (HR = 11.507; 95% CI: 2.697-49.104; p  = 0.001). Conclusion  The IMPROVE and Caprini risk scores were independent predictors of mortality and thrombotic events in severe COVID-19. With larger validation, this can be useful prognostic information.