Sex-Specific Prevalence, Incidence, and Mortality Associated With Atrial Fibrillation in Heart Failure.

Objectives: This study sought to investigate the mortality associated with atrial fibrillation (AF) in men and women with heart failure (HF) according to the sequence of presentation and rhythm versus rate control.

Background: The sex-specific epidemiology of AF in HF is sparse.

Methods: Using the Danish nationwide registries, all first-time cases of HF were identified and followed for all-cause mortality from 1998 to 2018.

Results: Among 252,988 patients with HF (mean age: 74 ± 13 years, 45% women), AF presented before HF in 54,064 (21%) and on the same day in 27,651 (11%) individuals, similar in women and men. Among patients without AF, the cumulative 10-year incidence of AF was 18.7% (95% confidence interval [CI]: 18.2% to 19.1%) in women and 21.3% (95% CI: 21.0% to 21.6%) in men. On follow-up (mean: 6.2 ± 5.8 years), adjusted mortality rate ratios were 3.33 (95% CI: 3.25 to 3.41) in women and 2.84 (95% CI: 2.78 to 2.90) in men if AF antedated HF, 3.45 (95% CI: 3.37 to 3.56) in women versus 2.76 (95% CI: 2.69 to 2.83) in men when AF and HF were diagnosed concomitantly, and 4.85 (95% CI: 4.73 to 4.97) in women versus 3.89 (95% CI: 3.80 to 3.98) in men when AF developed after HF. Compared with rate control for AF, a rhythm-controlling strategy was associated with lowered mortality in inverse probability-weighted models across all strata and in both sexes (hazard ratio: 0.75 to 0.83), except for women who developed AF after HF onset (hazard ratio: 1.03).

Conclusions: More than half of all men and women with HF will develop AF during their clinical course, with prognosis associated with AF being worse in women than men. Further studies are needed to understand the underlying mechanisms.