Outcomes Associated With Familial Versus Nonfamilial Atrial Fibrillation: A Matched Nationwide Cohort Study

BACKGROUND: We examined all‐cause mortality and long‐term thromboembolic risk (ischemic stroke, transient ischemic attack, systemic thromboembolism) in patients with and without familial atrial fibrillation (AF). METHODS AND RESULTS: Using Danish nationwide registry data, we identified all patients diagnosed with AF (1995–2012) and divided them into those with familial AF (having a first‐degree family member with a prior AF admission) and those with nonfamilial AF. We paired those with and without familial AF according to age, year of AF diagnosis, and sex in a 1:1 match. Using cumulative incidence and multivariable Cox models, we examined the risk of long‐term outcomes. We identified 8658 AF patients (4329 matched pairs) with and without familial AF. The median age was 50 years (interquartile range 43–54 years), and 21.4% were women. Compared with nonfamilial AF patients, those with familial AF had slightly less comorbid illness but similar overall CHA (2) DS (2)‐VASc score (P=0.155). Median follow‐up was 3.4 years (interquartile range 1.5–6.5 years). Patients with familial AF had risk of death and thromboembolism similar to those with nonfamilial AF (adjusted hazard ratio 0.91 [95% CI 0.79–1.04] for death and 0.90 [95% CI 0.71–1.14] for thromboembolism). CONCLUSIONS: Although family history of AF is associated with increased likelihood for development of AF, once AF developed, long‐term risks of death and thromboembolic complications were similar in familial and nonfamilial AF patients.