Anticoagulation strategy and safety in critically ill COVID-19 patients: a French retrospective multicentre study

Patients with critical illness due to COVID-19 exhibit increased coagulability associated with a high risk of venous thrombo-embolism (VTE). Data on prophylactic anticoagulation for these patients are limited and conflicting. The purpose of this study was to evaluate whether intermediate-dose prophylactic anticoagulation in patients with COVID-19 requiring ICU admission was associated with better outcomes compared to standard-dose prophylactic anticoagulation.

We retrospectively included adults admitted with severe COVID-19 to any of 15 ICUs, in 2020 or 2021. We compared the groups given intermediate-dose vs. standard-dose prophylactic anticoagulation. The primary outcome was all-cause day-90 mortality. Secondary outcomes were VTE (pulmonary embolism or deep vein thrombosis), ICU stay length, and adverse effects of anticoagulation.

Of 1174 included patients (mean age, 63 years), 399 received standard-dose and 775 intermediate-dose prophylactic anticoagulation. Of the 211 patients who died within 90 days, 86 (21%) received intermediate and 125 (16%) standard doses. After adjustment on early corticosteroid therapy and critical illness severity, there were no significant between-group differences in day-90 mortality (hazard ratio [HR], 0.73; 95%CI, 0.52-1.04; p = 0.09) or ICU stay length (HR, 0.93; 95%CI, 0.79-1.10; p = 0.38). Intermediate-dose anticoagulation was significantly associated with fewer VTE events (HR, 0.55; 95%CI, 0.38-0.80; p < 0.001). Bleeding events occurred in similar proportions of patients in the two groups (odds ratio, 0.86; 95%CI, 0.50-1.47; p = 0.57).

Mortality on day 90 did not differ between the groups given standard-dose and intermediate-dose prophylactic anticoagulation, despite a higher incidence of VTE in the standard-dose group.