Abstract
BACKGROUND: The impact of anemia on the safety and efficacy of anticoagulants in elderly patients with atrial fibrillation (AF) has not been elucidated. METHOD AND RESULTS: The J-ELD AF Registry is a large-scale, multicenter prospective observational study, of the one-year outcomes after administration of on-label doses of apixaban in Japanese patients with non-valvular AF aged ≥ 75 years. The entire cohort (3,015 patients from 110 institutions) was divided into three subgroups according to the WHO classification of anemia: normal (hemoglobin ≥ 13.0 g/dL in men and ≥ 12.0 g/dL in women, n = 1733, 57.5%), mild anemia (11.0 ≤ hemoglobin < 13.0 g/dL in men and 11.0 ≤ hemoglobin < 12.0 g/dL in women, n = 839, 27.8%), and moderate-severe anemia (<11.0 g/dL in both men and women, n = 443, 14.7%). The event rates (/100 person-years) for the normal, mild anemia, and moderate-severe anemia groups were 1.36, 1.81, and 1.99 for strokes or systemic embolisms (log-rank p = 0.556), 1.74, 1.16, and 4.02 for bleeding requiring hospitalization (log-rank p = 0.007), 2.03, 3.72, and 6.44 for total death (log-rank p < 0.001), and 0.86, 1.03, and 1.24 for cardiovascular death (log-rank p = 0.770), respectively. After adjusting for the confounders, moderate-severe anemia was an independent risk of total death (hazard ratio [95% confidence interval]; 2.21 [1.28-3.81], P = 0.004), but not for strokes or systemic embolisms and bleeding. CONCLUSIONS: In AF patients aged ≥ 75 years taking an on-label dose of apixaban, moderate-severe anemia was not an independent risk of a stroke or systemic embolism and bleeding requiring hospitalization.