Atrial fibrillation epidemiology and demographics

Overview
Atrial fibrillation is the most common arrhythmia found in clinical practice. It accounts for 1/3 of hospital admissions for cardiac rhythm disturbances, and the rate of admissions for AF has risen in recent years.

Epidemiology
Approximately 2.2 million individuals in the United States and 4.5 million in the European Union have AF.

The incidence of atrial fibrillation increases with age. The prevalence in individuals over the age of 80 is about 8%. In developed countries, the number of patients with atrial fibrillation is likely to increase during the next 50 years, due to the growing proportion of elderly individuals.

Prevalence
It should be noted that the prevalence of atrial fibrillation increases with increasing age, and its prevalence is increased among Caucasians, patients with hypertension and valvular heart disease. The prevalence in the general population is 0.4%.

Important genetic determinants may play a role in so far as the age-adjusted risk of developing atrial fibrillation among African-Americans is less than half that in Caucasians. The presence of atrial fibrillation often reflects the presence of underlying cardiac or lung disease. Indeed, the proportion of patients with “lone” atrial fibrillation, (that is those patients with atrial fibrillation in whom there is no cardiac or lung disease history) is low at about 12% of cases. Patients with atrial fibrillation tend to be older with a median age of 75 years. The proportion of patients with atrial fibrillation who are between 65 and 85 years of age is 70%, and females predominate in the very elderly (60% of atrial fibrillation patients over the age of 75 are women). Despite the fact that there are more very elderly women with atrial fibrillation, when age is adjusted for, the prevalence of atrial fibrillation is higher in men. The rate of rise per year in the risk of atrial fibrillation is slightly higher in the very elderly (1.5% per year for women and 2.0% per year for men over the age of 80 years). These rates are nearly 15 to 20 times higher than in those under the age of 40.

Incidence
Research has shown that the incidence of AF increased from less than 0.1% per year in those under 40 years of age to greater than 1.5% per year in women over 80 age and greater than 2% per year in men over 80 years of age. The age-adjusted incidence in the Framingham Heart Study found that in 38 years of follow-up, 20.6% of men and 26.0% of women who had developed AF had congestive heart failure at inclusion versus 3.2% and 2.9%, respectively, of those without AF. Among patients referred for treatment of heart failure, the 2-to-3-year incidence of AF was 5% to 10%. There was some evidence to suggest that incidence of AF may be lower in heart failure patients with pharmacologic intervention.