Prevalence of Venous Thromboembolism and Anticoagulant Use in Patients with COVID-19 in Alberta, Canada.

Abstract

COVID-19 causes a hypercoagulable state and increases the risk of venous thromboembolism (VTE). The primary objective was to identify VTE prevalence among patients with COVID-19 in one Canadian province. Secondary objectives were to identify the prevalence of bleeding, describe anticoagulation prescribing practices, and identify factors contributing to VTE in these patients. Adult patients admitted to Alberta hospitals between March and December 2020 with COVID-19 who had a length of stay of at least 72 hours were included in this retrospective study. VTE, bleeding events, and comorbidities were defined by International Classification of Diseases and Related Health Problems, 10th Revision codes. Cases of VTE and controls (no VTE) were matched on the basis of age older than 60 years, active cancer, and length of stay for the full cohort, as well as for a subgroup of patients with d-dimer data available, to assess for factors associated with VTE. A total of 2544 patients were included. Median age was 66 years, 1461 patients (57.4%) were male, median weight was 77.7 kg, and median d-dimer level on admission was 1.00 mg/L. The prevalence of VTE was 3.7% (n = 93) and that of major and clinically relevant non-major bleeding was 4.9% (n = 125). Of the total population, 1224 patients (48.1%) had standard prophylactic-dose anticoagulation, 460 (18.1%) received only higher-dose anticoagulation, 248 (9.7%) received both prophylactic- and higher-dose anticoagulation, and 612 (24.1%) had no anticoagulation data. Logistic regression showed that only the presence of d-dimer above 3 mg/L was associated with a significant odds ratio for VTE (7.04, 95% confidence interval 2.43-20.84). VTE prevalence among patients with COVID-19 was higher than baseline prevalence in Alberta. Analysis of prescribing practices demonstrated that a large proportion of patients received higher-dose anticoagulation.