Safety and efficacy of direct oral anticoagulants in stroke prevention in patients with atrial fibrillation complicated with anemia and/or thrombocytopenia: a retrospective cohort study

Background There are limited data about the clinical benefits and harm of direct oral anticoagulants (DOACs) in stroke prevention in patients with atrial fibrillation (AF) complicated with anemia or thrombocytopenia. Methods This is a multi-center retrospective cohort study involving 5469 AF patients from 15 hospitals in China. Patients were divided into three groups according to hemoglobin and platelet levels: Group 1 (hemoglobin male [greater than or equal to] 130 g/L; female [greater than or equal to] 120 g/L and platelet [greater than or equal to] 100 x 10.sup.9/L), Group 2 (hemoglobin male < 130 g/L; female < 120 g/L or platelet < 100 x 10.sup.9/L), and Group 3 (hemoglobin male < 130 g/L; female < 120 g/L and platelet < 100 x 10.sup.9/L). Patients in each category are further divided into two groups according to their stroke prevention strategies: rivaroxaban or dabigatran. Clinical results include major, minor, total bleeding, thrombosis, and the composite outcome of major bleeding and thrombosis. Results Higher hemoglobin levels were associated with a reduced risk of total bleeding and major bleeding, while platelet counts were not associated with any event. Compared with Group 1, Group 2 had a higher risk of major bleeding (aOR 1.70, 95%CI 1.12-2.57, P = 0.012), and the composite endpoint of major bleeding and thrombosis (aOR 1.70, 95%CI 1.19-2.44, P = 0.004). Compared with Group 1, Group 3 had a higher total bleeding risk (aOR 2.15, 95%CI 1.14-4.05, P = 0.018). Compared with dabigatran, rivaroxaban was associated with higher composite risk in Group 1 (aOR 2.91, 95% CI 1.66-5.16, P < 0.001) and Group 2 (aOR 3.05, 95%CI 1.46-6.39, P = 0.003), but there was no significant difference in Group 3 (aOR 1.78, 95%CI 0.23--13.54, P = 0.577). Conclusions Higher hemoglobin levels are associated with a reduced risk of total bleeding and major bleeding in patients with AF. Dabigatran was associated with better clinical outcomes than rivaroxaban in patients with anemia or thrombocytopenia but not in those with anemia and thrombocytopenia. Keywords: Anemia, Atrial fibrillation, Hemoglobin, DOACs, Platelet, Thrombocytopenia