Anticoagulation therapy using unfractionated heparin at a therapeutic dose for coronavirus disease 2019 patients with severe pneumonia: a retrospective historical control study

Aim Patients with severe coronavirus disease 2019 (COVID‐19) pneumonia often have complications of coagulopathy and thrombotic phenomena, which lead to high mortality. Whether administering systematic anticoagulant therapy is beneficial remains unclear. We report our experience using systemic anticoagulation with unfractionated heparin to treat severe COVID‐19. Methods We conducted a retrospective historical control study of severe COVID‐19 patients requiring mechanical ventilation who received prophylactic‐dose anticoagulation (April 1–May 25) or therapeutic‐dose anticoagulation (May 26–August 31) in the intensive care unit (ICU) of a tertiary emergency critical care medical center in Japan. The primary endpoints were in‐hospital mortality and anticoagulation therapy‐related adverse events. The secondary endpoints included thromboembolic events, administration of venovenous extracorporeal membrane oxygenation (ECMO), ventilator‐free days (VFDs), ICU‐free days, and the development of multiple organ dysfunction syndrome. Results A total of 29 and 33 patients were in the prophylactic‐dose and therapeutic‐dose groups, respectively. Background characteristics between the groups were not significantly different, although the therapeutic‐dose group had a significantly lower in‐hospital mortality rate [5 (17.2%) patients versus 0 (0.0%) patients; P = 0.033] and longer ICU‐free days (median [interquartile range]: 15 days [13–18] versus 5 days [0–13]; P = 0.008). Hemorrhagic‐events did not occur during the study period. Compared with the prophylactic‐dose group, the therapeutic‐dose group tended to have longer VFDs, was not treated with ECMO, and did not experience thromboembolic events and multiple organ dysfunction syndrome; however, the difference was not statistically significant. Conclusions Therapeutic‐dose anticoagulation may be beneficial for patients with severe COVID‐19 pneumonia requiring mechanical ventilation.