Introduction: Despite prophylactic anticoagulant treatments, thrombotic complications may develop in patients with Coronavirus disease 2019 (COVID-19). This study aimed to evaluate the factors influencing anti-Factor Xa activity in COVID-19 patients receiving low molecular weight heparin (LMWH).
Materials and methods: We prospectively evaluated 80 COVID-19 patients, diagnosed using polymerase-chain-reaction test, who were admitted to our clinic and administered LMWH; LMWH (enoxaparin) was applied according to the weight, D-dimer levels, and clinical condition of patients. Anti-Factor Xa activity in blood, drawn 4h after the 3rd dose of LMWH, were measured and a activity of <0.2 IU/ml was considered subprophylactic. Patients were followed up clinically and anti-Factor Xa activity were re-examined before discharge.
Results:Groups 1 and 2 included 13 and 67 patients with subprophylactic (mean±SD: 0.18±0.06) and prophylactic (mean±SD: 0.43±0.23) anti-Factor Xa activity, respectively. The proportion of eosinophils in patients was significantly higher in group 1 than in group 2 (mean±SD; 2.96±2.55 vs 0.90±1.28; p=0.001). At the time of discharge the eosinophilic proportion of patients was significantly higher (eosinophil %, mean±SD; 3.06±1.49 vs 2.07±1.92; p=0.001) but the activated partial thromboplastin time was significantly lower (22.34±1.38 vs 24.38±3.58; p=0.01) in group 1 than in group 2. Of 14 patients with eosinophil content >4%, 6 were in group 1 ((6/13) 46.2%) while 8 were in group 2 ((8/63) 11.9%); (p=0.009), and all had a D-dimer level <1µg/mL (p=0.03). ROC analysis for the presence of anticoagulation at subprophylactic level revealed an area under curve of 0.79 (95% CI:0.64-0.93); p=0.001).
Conclusions: Elevated eosinophil count is related to lower anti-factor Xa activity in patients with COVID-19 receiving LMWH. (NCT04507282)