Eligibility for Posthospitalization Venous Thromboembolism Prophylaxis in Hospitalized Patients With COVID-19: A Retrospective Cohort Study

Background A recent randomized trial, the MICHELLE trial, demonstrated improved posthospital outcomes with a 35-day course of prophylactic rivaroxaban for patients hospitalized with COVID-19 at high risk of venous thromboembolism. We explored how often these findings may apply to an unselected clinical population of patients hospitalized with COVID-19. Methods and Results Using a 35-hospital retrospective cohort of patients hospitalized between March 7, 2020, and January 23, 2021, with COVID-19 (MI-COVID19 database), we quantified the percentage of hospitalized patients with COVID-19 who would be eligible for rivaroxaban at discharge per MICHELLE trial criteria and report clinical event rates. The main clinical outcome was derived from the MICHELLE trial and included a composite of symptomatic venous thromboembolism, pulmonary embolus-related death, nonhemorrhagic stroke, and cardiovascular death at 35 days. Multiple sensitivity analyses tested different eligibility and exclusion criteria definitions to determine the effect on eligibility for postdischarge anticoagulation prophylaxis. Of 2016 patients hospitalized with COVID-19 who survived to discharge and did not have another indication for anticoagulation, 25.9% (n=523) would be eligible for postdischarge thromboprophylaxis per the MICHELLE trial criteria (range, 2.9%-39.4% on sensitivity analysis). Of the 416 who had discharge anticoagulant data collected, only 13.2% (55/416) were actually prescribed a new anticoagulant at discharge. Of patients eligible for rivaroxaban per the MICHELLE trial, the composite clinical outcome occurred in 1.2% (6/519); similar outcome rates were 5.7% and 0.63% in the MICHELLE trial's control (no anticoagulation) and intervention (rivaroxaban) groups, respectively. Symptomatic venous thromboembolism events and all-cause mortality were 6.2% (32/519) and 5.66% in the MI-COVID19 and MICHELLE trial control cohorts, respectively. Conclusions Across 35 hospitals in Michigan, ≈1 in 4 patients hospitalized with COVID-19 would qualify for posthospital thromboprophylaxis. With only 13% of patients actually receiving postdischarge prophylaxis, there is a potential opportunity for improvement in care.