Prevalence and Clinical Associates of Iron Deficiency in Patients With Atrial Fibrillation

Atrial fibrillation is the most frequent chronic arrhythmia with an increasing prevalence in developed and developing countries. Estimated number of individuals living with chronic atrial fibrillation is 33 million globally. In developed and developing countries, the number of elderly individuals increases steadily and the incidence varies from 0.21 to 0.41/1000 person-years depending on regional differences. Approximately half of atrial fibrillation cases are permanent (chronic), 25% are paroxysmal (ending within one week), and 25% are persistant atrial fibrillation (ending for a week, spontaneous or intervention).

Symptoms and signs of atrial fibrillation vary between individuals, and the clinical picture appears in a wide range of conditions ranging from asymptomatic events to thromboembolic events or patients with severe heart failure. The most common symptoms are; palpitations, fatigue, exercise intolerance, and systemic thromboembolic events in patients who do not receive appropriate anticoagulant treatment. Long-term follow-up, especially in persistent and permanent atrial fibrillation patients results in preserved ejection fraction heart failure and right heart failure. Prevention of thromboembolic events is the most important approach. Patients with paroxysmal, persistent and permanent atrial fibrillation have to take life-long oral anticoagulation therapy if they are at high risk for developing thromboembolic events. In patients with oral anticoagulant therapy, the risk of bleeding increases and hemorrhagic events are seen, ranging from life threatening asymptomatic blood loss to lethal cerebral hemorrhage.

Atrial fibrillation is considered as a chronic inflammatory disease. Both in general population and in patients with cardiac diseases, inflammatory mediators can alter atrial electrophysiology and structure, and thereby increase the tendency to develop atrial fibrillation. Enormous number of studies showed a clear association between inflammatory markers and thromboembolic events in atrial fibrillation.

Anemia is a frequently encountered problem in atrial fibrillation patients with a prevalence of 12.3%. Existing studies suggested an association between anemia and thromboembolic events in atrial fibrillation. However, current evidence supports that it is a marker for increased risk of bleeding after anticoagulant therapy, and two bleeding risk scores (ATRIA and HEAMORRHAGES) included presence of anemia as a component of risk assessment.

Despite of a clear association between anemia and unfavorable events in atrial fibrillation, none of the studies determined the type anemia in these patients so far. In a preliminary single center study, with relatively limited number of cases (n = 101), it is shown that 47.6% of patients with atrial fibrillation had ID according to the criteria used for heart failure patients. B12 (9.9%) and folic acid (12.9%) deficiencies were less frequent Again in the same study, the prevalence of ID was found to be twice as frequent as the paroxysmal atrial fibrillation group in the permanent atrial fibrillation group, suggesting that ID is associated with high sensitive C-reactive protein and N-terminal proBNP levels. The validation of this study findings in a larger, non-retrospective case-group and the clinical determinants of ID in patients with atrial fibrillation will be useful in the clinical evaluation of patients and in planning possible treatment alternatives.