In a nationwide registry study conducted in Denmark, half of all patients with heart failure developed atrial fibrillation (AF). Outcomes associated with AF were worse among women. The study data, published in JACC: Clinical Electrophysiology, outline the prevalence, incidence, and mortality associated with atrial fibrillation (AF) in patients with heart failure (HF).

Investigators extracted and evaluated data from the Danish nationwide hospital registry, which includes demographic and clinical information for all patients treated at hospitals in Denmark since 1978. They focused on all patients diagnosed with first-time HF between 1998 and 2018, identified using the appropriate diagnostic codes. Baseline information was collected at the time of HF diagnosis and included sex, age, use of cardiovascular medications, and medical comorbidities. The primary outcome was the onset of AF, defined as prevalent if occurring before HF diagnosis and incident if occurring with or after HF diagnosis.

The prevalence and 10-year incidence of AF were calculated and stratified by sex. Poisson regression was used to calculate the mortality rate ratios (RRs) associated with AF; Cox regression models were used to estimate risk of death following certain AF treatment methods. Models were adjusted for calendar year, age, and sex.

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The study cohort comprised 252,988 patients with HF, 45% of whom were women. Mean age at enrollment was 74 ± 13 years; mean follow-up time was 6.2 ± 5.8 years. A total of 54,064 (21%) patients presented with AF before HF onset and 27,651 (11%) were diagnosed with AF and HF concomitantly. During follow-up, 30,565 (12.1%) patients developed AF; the cumulative 10-year incidence was 18.7% (95% confidence interval [CI], 18.2-19.1) for women and 21.3% (95% CI, 21.0-21.6) for men.

In fully adjusted regression models, the mortality rate ratios (RRs) were significantly greater in patients with AF than patients with no AF (RR, 3.07; 95% CI, 3.02-3.12). The relationship was more pronounced in patients who developed AF after HF (RR, 4.32; 95% CI, 4.25-4.39) and particularly among women who developed incident AF (RR, 4.85; 95% CI, 4.73-4.97).

Women had a higher risk of death compared with men across all categories of AF diagnosis timing. Compared with rate control for AF, rhythm-controlling strategies appeared to improve mortality rates for women.

Results from this nationwide study underscore the close correlation between AF and HF. In sex-specific analyses, women had a comorbidity burden similar to that of men but were more likely to die from AF, particularly if diagnosed after HF. Study limitations include the homogenous patient sample, and the authors noted that the data may not be generalizable to patients of non-European ancestry.

Additionally, data on certain confounders were not available, including body mass index, alcohol and tobacco consumption, physical inactivity, and obstructive sleep apnea. More research is necessary, the authors emphasized, to further elucidate the epidemiology of AF in patients with HF.

They concluded that their findings ” add to the available body of evidence emphasizing the importance of AF as an additional factor for adverse outcomes in HF.”

“A rhythm-controlling strategy may mitigate some of the increased risk of mortality associated with AF, regardless of when during the clinical course (of HF) for AF develops,” the study authors stated.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry.

Please see the original reference for a full list of authors’ disclosures.


Barillas-Lara MI, Monahan K, Helm RH, et al. Sex-specific prevalence, incidence, and mortality associated with atrial fibrillation in heart failure. JACC Clin s. Published online April 28, 2021. doi: 10.1016/j.jacep.2021.02.021