The impacts of prophylactic anticoagulation therapy during hospitalization on long-term cardiovascular outcomes in high-risk COVID-19 patients amid the omicron wave of the pandemic.

Background: Although prophylactic anticoagulation therapy is suggested to be adopted in severe COVID-19 patients, its effects on the long-term cardiovascular (CV) outcomes, namely the risk of major adverse CV events(MACEs) in high-risk CV patients amid the omicron wave of the pandemic, remain unknown. Methods: We conducted this prospective cohort study of consecutive adults hospitalized COVID-19 between 19 April and 12 June 2022, COVID-19 patients with at least two CV risk factors or pre-existing CV diseases were enrolled. A propensity score matching(PSM) method was used to evaluated the effects of prophylactic anticoagulation therapy in hospital on long-term MACEs, including CV death, non-fatal myocardial infarction, non-fatal stroke, hospitalization due to unstable angina pectoris, coronary revascularization and arterial or venous thrombosis. Results: Two cohorts (with or without anticoagulants during hospitalization) of each 230 patients with balanced baseline characteristics were formed using PSM. During the 15-month follow-up period, 13 patients with anticoagulants and 29 patients without anticoagulants developed MACEs. Overall, the anticoagulation group had a significantly lower risk of MACEs than the control group (hazard ratio [HR] 0.431; 95 % confidence interval [CI]: 0.224-0.830, P = 0.010). Regarding specific constituents of MACEs, the differences were mainly reflected in arterial or venous thrombosis. The significantly lower HRs of overall MACEs were significantly observed in subgroup of age > 75 years, women, higher D dimer level, unvaccinated and non-nirmatrelvir-ritonavir prescribed patients. Conclusions: Prophylactic anticoagulation therapy during hospitalization was effective in reducing long-term MACEs among COVID-19 patients with CV risk factors or pre-existing CV diseases amid the omicron wave of the pandemic.