Bleeding and thrombosis outcomes in hospitalised COVID‑19 patients on low-molecular-weight heparin and antiplatelet therapy

Background. An increased incidence of thromboembolic events in hospitalised COVID‑19 patients has been demonstrated despite the use of low-molecular-weight heparin (LMWH). Antiplatelet therapy prior to admission and early in the disease course has been hypothesised to be protective against thrombosis.

Objectives. To describe the bleeding and thrombosis outcomes in hospitalised patients with confirmed COVID‑19 receiving LMWH, with and without concomitant antiplatelet therapy. Secondary objectives were to explore predictors of bleeding and thrombosis outcomes, and dosing practices of antiplatelet therapy and LMWH.
Methods. We conducted a descriptive, cross-sectional study of bleeding and thrombosis outcomes at Tygerberg Academic Hospital, Cape Town, South Africa, during the first COVID‑19 wave, in 808 hospitalised patients with confirmed COVID‑19 receiving LMWH with and without concomitant antiplatelet therapy. Multivariate logistic regression analysis was performed if predictors were deemed statistically and clinically significant.
Results. Patients receiving both LMWH and antiplatelet therapy had similar bleeding outcomes compared with patients only receiving LMWH (odds ratio (OR) 1.5; 95% confidence interval (CI) 0.6 - 4.0). Patients receiving both LMWH and antiplatelet therapy had increased odds of developing thrombosis compared with patients only receiving LMWH (OR 4.8; 95% CI 2.1 - 10.7).
Conclusion. The bleeding risk in COVID‑19 patients receiving both LMWH and antiplatelet therapy was not significantly increased. A potentially higher risk of thrombosis in patients receiving LMWH and antiplatelet therapy was observed. However, this could reflect confounding by indication. Randomised studies are required to further evaluate the use of antiplatelet therapy to treat hospitalised patients with COVID‑19.