Benefits of Early Rhythm Control Similar in Women and Men with Atrial Fibrillation, According to New Research

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Among women and men with recently detected atrial fibrillation (AF), early rhythm control (RC) can improve cardiovascular (CV) outcomes in patients of either sex without differences in safety, according to new research published in the Journal of the American College of Cardiology.

Findings come from a new prespecified subanalysis of the EAST-AFNET 4 (Early Treatment of AF for Stroke Prevention Trial), which showed a benefit of early RC therapy for early AF patients.

With emerging evidence on sex differences in incidence, prevalence, comorbidities, and outcomes of patients with AF, the aim of the current subanalysis was to “assess whether there are sex differences in clinical presentation, and whether the effectiveness and safety of early RC therapy interact with sex,” wrote first author Isabelle C. Van Gelder, MD, PhD, from the Department of Cardiology, University of Groningen, University Medical Center Groningen, Netherlands, and colleagues.

The primary outcome of EAST-AFNET 4 was time to a composite of death from CV causes, stroke, or hospitalization with worsening of heart failure or acute coronary syndrome. The primary safety outcome was a composite of death from any cause, stroke, or prespecified serious adverse events of special interest that captured complications of RC treatment, according to investigators.

Of all patients included, 1293 (46.4%) were women and 645 were randomized to receive early RC treatment and 648 to receive usual care. Compared with men, women were older (mean age of 71 years vs 70 years; P<.001), were more likely to have sinus rhythm at baseline (58% vs 51%; P<.001), were less likely to be asymptomatic (25% vs 36%; P<.001) and had a higher CHA₂DS₂-VASc score (3.7 vs 3; P<.001).

The types of early rhythm control therapy did not differ by sex (women, 88% antiarrhythmic drugs and 8.1% ablation; men, 86% antiarrhythmic drugs and 8% ablation; P=.82). At 2 years, the percentage of women and men from the early RC treatment group that were still receiving RC therapy did not differ significantly (P=.903), nor did the percentage of women and men from the usual care group not receiving RC therapy differ significantly (P =.401), according to investigators.

After a median of 5.1 years, the primary outcome occurred among women in the early RC group at a rate of 3.4 per 100 patient-years and in the usual care group at a rate of 4.7 per 100 patient-years (hazard ratio [HR] 0.72; 95% CI, 0.55-0.93), and in men, it occurred in the early RC group at a rate of 4.3 per 100 patient-years and in the usual care group at a rate of 5.2 per 100 patient-years (HR 0.83; 95% CI, 0.67-1.03). Van Gelder and colleagues concluded that treatment effect of early RC did not differ between sexes ( P_interaction=.408).

The primary safety outcome was comparable in both groups and did not differ by sex (women in early RC group, 15.8%; women in usual care group, 14.5%; men in early RC group, 17.2%; men in early group, 17.3%).

Serious adverse events related to RC were rare in both women and men, noted the research team. The proportion of patients in sinus rhythm at 2 years was greater in the early RC group than in the usual care group and did not vary by sex (women, 84.6% vs 65.2%; men, 80% vs 56.7%; P_interaction=.746). Investigators also found that symptoms improved to a similar extent in women and men.

Reference: Van Gelder IC, Ekrami NK, Borof K, et al. Sex differences in early rhythm control of atrial fibrillation in the EAST-AFNET 4 trial. J Am Coll Cardiol. 2023;81:845-847.