Clinical characteristics and risk factors for symptomatic venous thromboembolism in hospitalized COVID-19 patients: A multicenter retrospective study

BACKGROUND: High incidence of asymptomatic venous thromboembolism (VTE) has been observed in severe COVID-19 patients, but the characteristics of symptomatic VTE in general COVID-19 patients have not been described.

OBJECTIVES: To comprehensively explore the prevalence and reliable risk prediction for VTE in COVID-19 patients.

METHODS/RESULTS: This retrospective study enrolled all COVID-19 patients with a subsequent VTE in 16 centers in China from January 1 to March 31, 2020. A total of 2779 patients were confirmed with COVID-19. In comparison with 23,434 non-COVID-19 medical inpatients, the ORs for developing symptomatic VTE in severe and non-severe hospitalized COVID-19 patients were 5.94 (95%CI 3.91 to 10.09) and 2.79 (95%CI 1.43 to 5.60), respectively. When 104 VTE cases and 208 Non-VTE cases were compared, pulmonary embolism cases had a higher rate for in-hospital death (OR 6.74, 95%CI 2.18 to 20.81). VTE developed at a median of 21 days (IQR 13.25 to 31) since onset. Independent factors for VTE were advancing age, cancer, longer interval from symptom onset to admission, lower fibrinogen and higher D-dimer on admission, and D-dimer increment (DI) ≥ 1.5 fold; of these, DI ≥ 1.5 fold had the most significant association (OR 14.18, 95%CI 6.25-32.18, P = 2.23 × 10-10 ). A novel model consisting of simple 3 coagulation variables (fibrinogen and D-dimer levels on admission, and DI ≥ 1.5 fold) showed good prediction for symptomatic VTE (AUC 0.865, 95%CI 0.822 to 0.907, sensitivity 0.930, specificity 0.710).

CONCLUSIONS: There is an excess risk of VTE in hospitalized COVID-19 patients. The novel model can help early identification of patients who are at high risk for VTE.