Newly diagnosed atrial fibrillation and hospital utilization in heart failure: a nationwide cohort study

Aims: Atrial fibrillation (AF) constitutes a major burden to health services, but the importance of incident AF in patients with heart failure (HF) is unclear. We examined the associations between incident AF and hospital utilization in patients with HF. Methods and results: In a nationwide matched-cohort study of HF patients, we identified patients diagnosed with incident AF between 2008 and 2018 in the Danish Heart Failure Registry (N = 4463), and we compared them to matched referents without AF (N = 17 802). Incident AF was associated with a multivariable-adjusted 4.8-fold increase (95% CI 4.1–5.6) and 4.3-fold increase (95% CI 3.9–4.8) in the cumulative incidence of inpatient and outpatient contacts within 30 days, respectively. At 1 year, the cumulative incidence ratios were 1.8 (95% CI 1.7–1.9) and 1.4 (95% CI 1.4–1.5). Incident AF was also associated with increases in the total numbers of inpatient and outpatient hospital contacts within 30 days (multivariable-adjusted rate ratio 1.4, 95% CI 1.4–1.5, and 1.6, 95% CI 1.6–1.7, respectively). At 1 year, the ratios were 2.2 (95% CI 2.1–2.3) and 2.0 (95% CI 1.9–2.1). The multivariable-adjusted proportion of bed-day use among HF patients with incident AF was 10.9-fold (95% CI 9.3–12.9) higher at 30 days and 5.3-fold (95% CI 4.3–6.4) higher at 1 year compared with AF-free referents. Conclusions: Incident AF in HF is associated with earlier hospital contact, more hospital contacts, and more hospital bed-days. More evidence on interventions that may prevent the risk and subsequent burden of AF in HF is urgently needed.