Characteristics and outcomes of atrial fibrillation patients with or without specific symptoms: results from the PREFER in AF registry

Background Atrial fibrillation (AF) is a common condition that is a major cause of stroke. A significant proportion of patients with AF are not classically symptomatic at diagnosis or soon after diagnosis. There is little information comparing their characteristics, treatment, and outcomes of patients with symptoms, which predominate in clinical trials to those without. Methods We analysed data from the Prevention of Thromboembolic Events – European Registry in Atrial Fibrillation (PREFER in AF). This was a prospective, real-world registry with a 12-month follow-up that included AF patients aged 18 years and over. Patients were divided into those with and without AF symptoms using the European Heart Rhythm Association (EHRA) score (category I vs. categories II – IV). Results Of the 6,196 patients (mean age 72 years) with EHRA scores available, 501 (8.1%) were asymptomatic. A lower proportion of asymptomatic patients was female (22.8% vs. 41.2%), with less noted to have heart failure and coronary artery disease (p<0.01 for all). There were no differences in terms of the prevalence of diabetes, obesity, or prior stroke. Asymptomatic patients had a lower CHA2DS2-VASc score (2.9±1.7 vs. 3.4±1.8; p<0.01) and HAS-BLED score (1.8±1.1 vs. 2.1±1.2; p<0.01). During the one-year follow-up, adverse events occurred at similar frequencies in asymptomatic and symptomatic patients (1.6% vs. 0.8% for ischemic stroke; p=0.061; 1.4% vs. 1.3% for transient ischaemic attack; p=0.840). Patients with higher CHA2DS2-VASc and HAS-BLED scores experienced more events, independent of symptoms. Antithrombotic therapy was comparable for both groups at baseline and at follow-up. Conclusions The similar clinical characteristics and frequency of adverse events between asymptomatic and symptomatic AF patients revives the question of whether screening programmes to detect people with asymptomatic AF are worthwhile, particularly in those aged 65 and over potentially likely to have clinical and economic benefits from anticoagulants. This evidence may be informative if clinicians may not be comfortable participating in future clinical trials, leaving asymptomatic patients with AF and high stroke risk without anticoagulation.