A prospective 5-year follow-up after population-based systematic screening for atrial fibrillation.

Aims: Thrombo-embolic stroke risk in atrial fibrillation (AF) is significantly reduced with oral anticoagulant (OAC) treatment. Atrial fibrillation is often asymptomatic (silent) and therefore undiagnosed. The long-term course of silent AF as well as OAC treatment adherence after AF screening is not known. We aim at studying long-term adherence to OAC treatment, AF symptoms, and stroke incidence on population level after systematic AF screening. Methods and results: All inhabitants in a Swedish municipality who were born in 1934 and 1935 (n = 1335) were invited to participate in an AF screening trial between 2010 and 2012. Participants with a previously known or screening-detected AF were invited to a 5-year follow-up. Time trends of ischaemic stroke incidence were compared for population groups residing in the intervention municipality and in a surrounding control area where no AF screening trial was carried out. After the screening procedure, 103 of 121 participants (85%) with AF were treated with OAC. At the follow-up examination, 94 of 106 living patients (88%) were still on OAC treatment. Among the 23 long-term surviving patients who were diagnosed with paroxysmal AF during screening, 6 had developed permanent silent AF. The incidence of ischaemic stroke between ages 76-80 years declined significantly after the AF screening trial in the intervention area (P = 0.003) but not in the control area. Conclusion: Adherence to OAC treatment 5 years after AF screening was high. Silent AF has a natural course similar to symptomatic AF. The observed incidences of ischaemic stroke suggest a beneficial population-level effect of systematic AF screening.