Incidence & outcomes of clinically significant bleeding events in critically ill COVID-19 patients receiving Therapeutic dose AntiCoagulanTs: A retrospective cohort study (INTerACT study)

Background & objectives: The high mortality associated with the thrombotic events in hospitalized COVID-19 patients resulted in the usage of anticoagulants in varying doses. Whether high-dose anticoagulants have led to better outcomes or higher incidence of clinically significant bleeding events is debatable. Thus, this study was conducted to find the incidence of clinically significant bleeding events in moderate-to-severe COVID-19 ARDS (acute respiratory distress syndrome) patients on therapeutic anticoagulation and their outcomes.

Methods: In this retrospective, single-centre study of 155 critically ill COVID-19 patients, the incidence of clinically significant bleeding was observed. Multivariate regression models were used to evaluate the association between anticoagulant regimen, coagulation and inflammatory markers with the incidence of bleeding and thrombotic events.

Results: The incidence of clinically relevant non-major bleeding was 33.54 per cent (26.17-41.46%) and major bleeding was 9.03 per cent (5.02-14.69%). The anticoagulation intensity at baseline had a high odds of major bleeding when enoxaparin and dual antiplatelet therapy were used together [adjusted odds ratio OR of 434.09 (3.81-49502.95), P<0.05]. At admission, bleeders had a poorer PaO₂/FiO₂ ratio with more patients on invasive ventilation. At the time of bleeding, the bleeders had a higher D-dimer, ferritin, C-reactive protein and procalcitonin compared to non-bleeders. The subhazard ratio for death in bleeders was 3.35 (95% confidence interval, 1.97-5.65; P<0.001).

Interpretation & conclusions: The incidence of bleeding in critically ill COVID-19 patients on therapeutic anticoagulation may increase with the severity of the disease as well as with concurrent use of dual antiplatelets. Major bleeding may also contribute to higher mortality.