Patients with atrial fibrillation (AF) and atrial flutter (AFL) differ with regard to clinical outcomes, including risk for ischemic stroke, heart failure hospitalizations, and rate of all-cause mortality, and these outcomes may be driven by CHA2DS2-VASc scores, according to a study published in JAMA Network Open.
The Taiwan National Health Insurance Research Database was used to identify a cohort of patients with AF (n=188,811), AFL (n=6121), and a group of age- and sex-matched controls (n=24,484). Study investigators compared the clinical outcomes of ischemic stroke risk, heart failure hospitalization, and all-cause mortality among the groups following stratification by CHA2DS2-VASc score. The score ranged from 0 to 9, with higher scores indicating higher risk for ischemic stroke.
Compared with patients with AFL and controls, patients with AF were older, more often female, and had higher CHA2DS2-VASc scores. The incidence densities of ischemic stroke were 3.08 (95% CI, 3.03-3.13), 1.45 (95% CI, 1.28-1.62), and 0.97 (95% CI, 0.92-1.03) for AF, AFL, and control participants, respectively. For heart failure hospitalizations in the AF, AFL, and control cohorts, the incidence densities were 3.39 (95% CI, 3.34-3.44), 1.57 (95% CI, 1.39-1.74), and 0.32 (95% CI, 0.29-0.35), respectively. Additionally, all-cause mortality incidence densities were 17.8 (95% CI, 17.7-17.9) in the AF cohort, 13.9 (95% CI, 13.4-14.4) in the AFL cohort, and 4.2 (95% CI, 4.1-4.4) in the control group.
Overall, the incidence densities for all 3 clinical outcomes were significantly higher in patients with AF vs matched controls. The incidence of ischemic stroke was significantly higher in patients with AFL vs matched controls only at CHA2DS2-VASc scores of 5 to 9. In addition, the ischemic stroke and heart failure hospitalization incidences were higher in the AF cohort vs the AFL cohort when CHA2DS2-VASc scores were ≥1. The all-cause mortality incidence was also significantly higher in individuals with AF vs those with AFL at CHA2DS2-VASc scores of 1 to3.
Limitations of the study included its retrospective design and the reliance on insurance database records to identify AF and AFL clinical outcomes.
Further research may be needed to reassess “the net clinical benefit of oral anticoagulants to prevent ischemic stroke in patients with AFL according to the currently recommended level of the CHA2DS2-VASc score.”
Lin Y-S, Chen Y-L, Chen T-H, et al. Comparison of clinical outcomes among patients with atrial fibrillation or atrial flutter stratified by CHA2DS2-VASc score. JAMA Network Open. 2018;1(4):e180941.