Screening-Detected Atrial Fibrillation and Cardiovascular Outcomes in Working-Age Adults

BACKGROUND: Early detection of atrial fibrillation (AF) is essential for preventing ischemic stroke and other cardiovascular complications. However, the incidence and prognosis of AF in the general middle-aged population remain unclear. In Japan, annual health screenings for employees include mandatory ECGs, offering a unique opportunity to fill this evidence gap. METHODS: This retrospective cohort study aimed to evaluate the incidence and subsequent cardiovascular outcomes of screening-detected AF in the general working population in Japan, using the Japan Health Insurance Association database, which covers one-quarter of the working-age population of that country. From individuals 35 to 59 years of age who underwent annual health screenings between April 2015 and March 2020, excluding those with a history of cardiovascular disease, those with initial AF detection upon screening ECGs were identified. The primary outcome was hospitalization for ischemic stroke. The secondary outcomes were all-cause death and hospitalization for heart failure. The association between screening-detected AF and outcomes was evaluated using adjusted subdistribution hazard models compared with matched controls. RESULTS: Among 9.5 million individuals included in our study, 11 790 initial AF cases (42.4 of 100 000 person-years 95% CI, 41.6–43.1) were detected. Individuals with AF were older (mean age, 50.9 versus 46.3 years) and more likely to be male (91.6% versus 63.6%) compared with non-AF cases. Among these individuals with screening-detected AF, the 3-year incidences of ischemic stroke, all-cause death, and heart failure were 1.83% (95% CI, 1.57–2.09), 0.78% (95% CI, 0.61–0.95), and 3.87% (95% CI, 3.50–4.24), respectively. Compared with age- and sex-matched controls, individuals with AF had a higher risk of incident ischemic stroke (hazard ratio, 5.38 95% CI, 4.51–6.42), all-cause death (hazard ratio, 1.98 95% CI, 1.66–2.36), and heart failure (hazard ratio, 18.35 95% CI, 15.10–22.31). CONCLUSIONS: AF was detected in one out of 2400 screening ECGs among the middle-aged population in Japan, with higher relative risks of ischemic stroke and heart failure, compared with those without AF. These findings highlight the association of screening-detected AF with stroke and heart failure, warranting further study into AF as an early sign of heart failure and optimal cardiovascular risk reduction strategies after AF detection in the general middle-aged population.