Associations of anemia with death and major bleeding in patients with atrial fibrillation: A report from the Chinese Atrial Fibrillation Registry Study

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.