Association of iron deficiency anemia with the development of paroxysms of atrial fibrillation within a year after pharmacological cardioversion with amiodarone

BACKGROUND: Anemia is a common problem with atrial fibrillation. There is a limited number of studies examining the role of iron deficiency anemia in the course of atrial fibrillation. AIM: To evaluate the association of iron deficiency anemia with the development of recurrent atrial fibrillation within 12 months in patients after pharmacological cardioversion with amiodarone. MATERIAL AND METHODS: The study included 198 patients over 18 years of age [120 (60.6%) men and 78 (39.4%) women, median age 71 (63.2; 77) years] with paroxysmal non-valvular atrial fibrillation and duration of paroxysm 48 h, after successful pharmacological cardioversion with amiodarone. The group with anemia included 99 patients (all had iron deficiency anemia), the group without anemia included 99 people. Patients with anemia were older; the groups were comparable in other main indicators. The development of recurrent atrial fibrillation over 1 year of follow-up was assessed by the Kaplan–Meier method and the Cox proportional hazards model. Differences were considered statistically significant at a p value 0.05. RESULTS: In the iron deficiency anemia group, symptomatic relapses of atrial fibrillation developed in 40.4% of patients during 1 year of observation; in the group without anemia — in 25.3% of patients (p=0.003). Kaplan–Meier analysis showed that iron deficiency anemia is associated with an increased risk of developing recurrent atrial fibrillation within 1 year after pharmacological cardioversion with amiodarone, relative risk 1.87 (p=0.014). Comparison of the risks associated with iron deficiency anemia and iron deficiency (regardless of the presence of anemia) showed a greater risk of recurrent atrial fibrillation associated with iron deficiency than with anemia (for interaction p=0.014). CONCLUSION: A comparison of the risks of developing recurrent atrial fibrillation in patients with iron deficiency itself and in patients with iron deficiency anemia showed a greater influence on the prognosis of recurrent atrial fibrillation by the presence of iron deficiency.