Abstract Body (Do not enter title and authors here):
Background:
COVID-19 is a multiorgan disease characterized by a prothrombotic state and increased risk of venous thromboembolism (VTE), especially in hospitalized patients. Although prior studies have attempted to identify predictors of VTE, restricted sample size and use of administrative claims data have limited such analyses. We conducted a multivariable analysis to identify predictors of VTE in hospitalized patients with COVID-19 in a multicenter patient-level registry.

Methods:
We utilized data from the CORONA-VTE Network, a US multicenter registry of 10,420 adult (≥18 years) patients with PCR-confirmed COVID-19 of whom 3,844 were hospitalized. The primary outcome was time-to-first-event for a composite of adjudicated pulmonary embolism and deep vein thrombosis (e.g. lower extremity, mesenteric, gonadal vein, etc.) during 90-day follow-up. The candidate variables were selected by a priori clinical consensus. The variables with ≥20% missing data were excluded, whereas those with missing data <20% were estimated using multiple imputation. Selected variables included prophylactic anticoagulation during hospitalization, corticosteroid therapy, female sex, baseline prescriptions of anticoagulants and statins, use of hormone replacement therapy, history of peripheral artery disease, prior VTE, and known thrombophilia. Subsequently, we conducted cox proportional hazard regression adjusted for the selected variables for each imputed dataset and pooled the estimated HRs for reporting (p<0.05 for significance).

Results:
The overall rate of VTE was 5.39%. The covariates associated with increased risk of VTE were history of VTE (HR: 1.71; 95% CI: 1.11-2.63), corticosteroid therapy (HR: 1.76; 95% CI: 1.32-2.33) and known thrombophilia (HR: 3.56; 95% CI: 1.54-8.21). The covariates associated with decreased risk of VTE were anticoagulation at baseline (HR: 0.42; 95% CI: 0.26-0.69), antecedent use of statins (HR: 0.67; 95% CI: 0.50-0.90), and prophylactic anticoagulation during hospitalization (HR: 0.52; 95% CI: 0.38-0.71).

Conclusions:
While prior VTE, corticosteroid therapy, and known thrombophilia were associated with increased risk of VTE, prescriptions of anticoagulation and statins were associated with a decreased risk.