Atrial fibrillation (AFib) is the most common sustained cardiac arrhythmia, characterized by an irregular and often rapid heart rhythm originating in the upper chambers of the heart, the atria. In a healthy heart, electrical signals travel in a coordinated way, but with AFib, these signals become chaotic, causing the atria to quiver instead of fully contracting. This chaotic activity reduces the heart’s ability to pump blood efficiently to the rest of the body. Understanding the frequency of AFib is relevant because this condition is strongly linked to an increased risk of stroke, heart failure, and mortality.
Global and National Prevalence Rates
Atrial fibrillation affects tens of millions of people worldwide, representing a considerable global health burden. In 2017, the estimated number of prevalent cases globally reached approximately 37.57 million individuals, representing roughly 0.51% of the world’s population. This figure has been steadily rising, though high-income countries historically report the highest relative prevalence rates.
In the United States, current estimates suggest that approximately five million adults are living with AFib, translating to an overall prevalence of about 3.89% among the adult population. Incidence, which measures the rate of new cases per year, also demonstrates the condition’s high occurrence. Globally, about 3.05 million new cases of AFib were reported in 2017.
Within the US, prevalence varies by sex and geography. A recent analysis found the prevalence was 4.87% for males and 3.11% for females. Geographically, rural areas reported a higher rate (5.29%) compared to urban areas (3.66%).
Demographic Factors Driving Occurrence
The occurrence of AFib is influenced by specific demographic characteristics and the presence of other health conditions. Age is the most significant factor, as the lifetime risk of developing AFib for those aged 40 years or older is estimated to be about one in four. For adults under the age of 50, the prevalence of AFib is very low, around 0.26%, but it dramatically increases with each decade of life. The prevalence surges to nearly 25% for individuals aged 90 and older, illustrating the strong age dependency of the condition.
Differences in occurrence are also observed between sexes. Men generally have a higher age-standardized incidence rate than women and show a higher overall prevalence. Despite the lower incidence in women, they often experience a higher risk of AFib-related complications, such as stroke.
Underlying medical conditions, known as co-morbidities, also increase the likelihood of AFib occurrence. Hypertension, or high blood pressure, is a leading risk factor, associated with a 1.7- to 2.5-fold increased risk of developing the arrhythmia. Other cardiometabolic factors, including obesity and diabetes mellitus, are strongly linked to new cases of AFib.
Common Comorbidities
Conditions frequently observed in people with AFib include:
- Diabetes is associated with a 1.28-fold increased relative risk.
- Obstructive sleep apnea.
- Chronic kidney disease.
- Heart failure.
Temporal Trends in AFib Incidence
The overall prevalence of atrial fibrillation is increasing over time, driven primarily by shifts in global demographics and improved medical detection. Between 1990 and 2017, the global count of prevalent AFib cases nearly doubled, rising from approximately 19.14 million to 37.57 million cases. This increase is largely attributable to the progressive aging of the world’s population, as AFib is predominantly a condition of older adults.
Projections suggest that this upward trajectory will continue. Estimates indicate that by 2050, between 6 and 12 million people will be affected in the United States alone. Similarly, the number of individuals with AFib in Europe is projected to reach 17.9 million by 2060.
The rise in AFib occurrence is also linked to the increasing prevalence of associated risk factors like obesity, hypertension, and diabetes. Advancements in medical care mean that people with other heart conditions are surviving longer, increasing the pool of individuals susceptible to developing AFib later in life.