Characteristics and outcomes of atrial fibrillation in patients without traditional risk factors: an RE-LY AF registry analysis

Aims: Data on patient characteristics, prevalence, and outcomes of atrial fibrillation (AF) patients without traditional risk factors, often labelled 'lone AF', are sparse. Methods and results: The RE-LY AF registry included 15 400 individuals who presented to emergency departments with AF in 47 countries. This analysis focused on patients without traditional risk factors, including age >= 60years, hypertension, coronary artery disease, heart failure, left ventricular hypertrophy, congenital heart disease, pulmonary disease, valve heart disease, hyperthyroidism, and prior cardiac surgery. Patients without traditional risk factors were compared with age- and region-matched controls with traditional risk factors (1:3 fashion). In 796 (5%) patients, no traditional risk factors were present. However, 98% (779/796) had less-established or borderline risk factors, including borderline hypertension (130-140/80-90mmHg; 47%), chronic kidney disease (eGFR<60mL/min; 57%), obesity (body mass index>30; 19%), diabetes (5%), excessive alcohol intake (>14 units/week; 4%), and smoking (25%). Compared with patients with traditional risk factors (n=2388), patients without traditional risk factors were more often men (74% vs. 59%, P<0.001) had paroxysmal AF (55% vs. 37%, P<0.001) and less AF persistence after 1 year (21% vs. 49%, P<0.001). Furthermore, 1-year stroke occurrence rate (0.6% vs. 2.0%, P=0.013) and heart failure hospitalizations (0.9% vs. 12.5%, P<0.001) were lower. However, risk of AF-related re-hospitalization was similar (18% vs. 21%, P=0.09). Conclusion: Almost all patients without traditionally defined AF risk factors have less-established or borderline risk factors. These patients have a favourable 1-year prognosis, but risk of AF-related re-hospitalization remains high. Greater emphasis should be placed on recognition and management of less-established or borderline risk factors.