Continuation of therapeutic anticoagulation before and during hospitalization is associated with reduced mortality in COVID-19 ICU patients

Abstract

Background: Literature has well established COVID-19 associated coagulopathy with resulting thrombotic complications including microthrombi as an underlying mechanism leading to severe respiratory disease. Therapeutic anticoagulation (TAC) for COVID-19 patients has therefore been widely trialed to combat COVID-19’s coagulopathic effects. However, literature has yet to define which population of patients TAC benefits; the most current randomized controlled trials (RCTs) reveal TAC to be possibly beneficial to moderately-ill hospitalized COVID-19 patients, whereas benefits did not outweigh risks in critically-ill ICU patients. Importantly, these studies excluded patients who received prehospital TAC. We examined outcomes in critically ill COVID-19 ICU patients who received TAC vs prophylactic anticoagulation (PAC) and specifically whether prehospital TAC effected outcomes. Methods: Retrospective cohort study of 132 COVID-19 ICU patients admitted March-June, 2020. Initial clinical practice provided PAC, as literature demonstrating COVID-19 associated coagulopathy and increased thromboembolic complications emerged, a TAC protocol was initiated. Results: 130 patients were included in the study, 95 of whom received TAC and 35 PAC. There was 50.8% overall mortality, with lower mortality in the TAC vs PAC group (46.3% vs 62.9%, p=0.094). There were few thromboembolic and hemorrhagic complications, with no significant difference between TAC and PAC patients. Of 24 patients anticoagulated prior to and during hospitalization, only 1 (4.2%) died, whereas the mortality was 60.6% among patients therapeutically anticoagulated during hospitalization only (p<0.001). Multivariable analysis revealed patients who received prehospital and in hospital TAC had a 92% lower risk of death (p=0.008) compared to in hospital only TAC and PAC patients. Conclusions: Overall, therapeutic anticoagulation did not result in mortality benefit to COVID-19 ICU patients compared to prophylactic anticoagulation. However, a sub-population of patients who received TAC both prior to and during hospitalization had a 12-fold lower risk of death. This suggests a protective effect of TAC when it is continued before and during hospitalization. RCTs are needed to specifically examine this subset of COVID-19 patients.