Afib in the Family Not Riskier for Outcomes

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Atrial fibrillation (afib) that runs in the family makes incidence more likely, but the prognosis is the same as in nonfamilial cases, a Danish registry study showed.

Afib patients with a first-degree family member who also had been admitted for afib carried similar risks as did nonfamilial cases for both death (adjusted HR 0.91, 95% CI 0.79–1.04) and thromboembolism (adjusted HR 0.90, 95% CI 0.71–1.14) during a median 3.4 years of follow-up.

While , the similar outcomes "do not suggest different antithrombotic treatment approaches for familial atrial fibrillation patients and the general atrial fibrillation population," Anna Gundlund, MD, of Herlev-Gentofte Hospital in Hellerup, Denmark, and colleagues concluded in the Journal of the American Heart Association.

In an accompanying editorial, Laurent Fauchier, MD, PhD, of Centre Hospitalier Universitaire Trousseau in Tours, France, and colleagues agreed that "the perceived possible different effect of familial pattern against the risk of death and thromboembolic events seems irrelevant in AF patients when using a contemporary risk stratification scheme, the CHA₂DS₂-VASc score."

They called the study unique in largely avoiding selection bias through a national dataset and noted that, despite some missing clinical characteristics, "the multivariable analyses seem quite robust and they are unlikely to be reproduced easily in many other cohorts."

The study from Danish nationwide registry data included 8,658 patients diagnosed with afib from 1995 through 2012 with both parents known, matched 1:1 for familial afib status as well as age, year of afib diagnosis, and sex.

The familial afib group had slightly less comorbid illness, albeit similar overall CHA₂DS₂-VASc score (P=0.155), which led to lower crude mortality risk (HR 0.85, 95% CI 0.74-0.97). While multivariable risk adjustment eliminated significance of that difference in mortality risk, Fauchier's group wrote:

"Maybe the study in 4,329 cases still lacks some power for definite conclusions and the researchers acknowledge this point, but a 17% lower risk of death has to be considered beyond statistical significance. This is a quite intriguing result, which is uneasy to explain at this stage. Maybe a better awareness about atrial fibrillation may lead to an earlier and holistic management in patients with familial atrial fibrillation. This would be an interesting part of a general strategy of atrial fibrillation screening in the population, advocating that an early detection and treatment of patients with asymptomatic atrial fibrillation before the first complications occur is a recognized priority for the prevention of cardiovascular events."

Compared with the entire afib population in the registry, the familial afib patients were less likely to be female (21% versus 47% were women) and were younger at diagnosis (median age 50 vs 77).

Looking only at family history of premature diagnosis before age 70, there still was no difference in thromboembolic risk compared with matched nonfamilial cases, but all-cause mortality came out significantly lower (HR 0.83, 95% CI 0.69-0.99).

Aside from limitations noted by the editorialists, Gundlund's group pointed to the retrospective nature of the study precluding conclusions of causality and the large number of afib patients excluded from the analysis due to lack of complete information about both parents.