Abstract
BACKGROUND: Anemia is a common comorbidity in patients with atrial fibrillation (AF). Reports on the association of anemia and adverse events in patients with AF, especially from Asia, are limited. METHODS AND RESULTS: Based on data from the Chinese Atrial Fibrillation Registry Study (CAFR), a total of 18,106 AF patients enrolled between August 2011 and December 2018 had hemoglobin (Hb) values recorded at baseline. Patients were classified into three groups according to Hb levels: 15,606 patients (86.2%) into the no anemia group (male Hb≥130 g/L; female Hb≥120 g/L), 1800 (9.9%) with mild anemia (male 110≤Hb<129 g/L; female 110≤Hb<119 g/L), and 700 (3.9%) with moderate to severe anemia (Hb≤109 g/L). Multivariable Cox regression models were used to determine if anemia was independently associated with all-cause death, cardiovascular death, or major bleeding, after adjusting for confounders. Anemia was present in 13.8% of the population at baseline. During a median follow-up of 4.01 years, the incidences of all-cause death (1.8, 4.9, and 8.9 per 100 person-years), cardiovascular death (1.0, 2.9, and 4.5 per 100 person-years), and major bleeding (0.5, 0.6, and 0.7 per 100 person-years) were gradually accentuated in patients with no anemia, mild anemia, and moderate to severe anemia, respectively. Compared with patients with no anemia, those with anemia had higher risks for all-cause death (mild anemia; adjusted hazard ratio [HR]: 1.22, 95% confidence interval [CI]: 1.08-1.38; moderate to severe anemia; adjusted HR: 1.53, 95% CI: 1.31-1.77); and cardiovascular death (mild anemia; adjusted HR: 1.29, 95% CI: 1.10-1.52; moderate to severe anemia; adjusted HR: 1.27, 95% CI: 1.03-1.57), but not for major bleeding. The association between anemia and all-cause death was similar among subgroups stratified by sex, kidney function, anticoagulant, or ablation therapy. CONCLUSIONS: Anemia was associated with increased risks of all-cause death, cardiovascular death, but no major bleeding in AF patients. The effect of anemia correction on the prognosis of patients with AF requires further study.