While people with atrial fibrillation or atrial flutter had worse outcomes than people without either, for some outcomes, risk varied by degree of CHA2DS2-VASc score, researchers reported in JAMA Network Open.
The researchers conducted a nationwide cohort study using data from the Taiwan National Health Insurance Research Database between 2001 and 2012. The population included 188,811 patients with AF (mean age, 74 years; 56% men), 6,121 patients with atrial flutter (mean age, 68 years; 61% men) and 24,484 controls without either condition matched by age and sex (mean age, 67 years; 61% men).
Participants were stratified by CHA2DS2-VASc score; patients with AF had a higher mean CHA2DS2-VASc score than patients with atrial flutter or controls. Outcomes of interest included ischemic stroke, hospitalization for HF and all-cause mortality.
After stratification by CHA2DS2-VASc score, incidence densities for all three outcomes were higher in the AF group vs. the control group, Yu-Sheng Lin, MD, from the division of cardiology, department of internal medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan, and colleagues wrote.
For ischemic stroke, the incidence densities were as follows: 3.08 per 100 person-years in the AF cohort (95% CI, 3.03-3.13), 1.45 per 100 person-years in the atrial flutter cohort (95% CI, 1.28-1.62) and 0.97 per 100 person-years in controls (95% CI, 0.92-1.03).
For HF hospitalization, the incidence densities were as follows: 3.39 per 100 person-years in the AF cohort (95% CI, 3.34-3.44), 1.57 per 100 person-years in the atrial flutter cohort (95% CI, 1.39-1.74) and 0.32 per 100 person-years in controls (95% CI, 0.29-0.35).
For all-cause mortality, the incidence densities were 17.8 per 100 person-years in the AF cohort (95% CI, 17.7-17.9), 13.9 per 100 person-years in the atrial flutter cohort (95% CI, 13.4-14.4) and 4.2 per 100 person-years in controls (95% CI, 4.1-4.4).
Compared with controls, the atrial flutter cohort had consistently higher incidences of HF hospitalization and all-cause mortality across CHA2DS2-VASc scores, but incidence of ischemic stroke was higher for atrial flutter cohort only if the CHA2DS2-VASc score was 5 to 9, Lin and colleagues wrote.
Compared with the atrial flutter cohort, the AF cohort had higher incidence of ischemic stroke and HF hospitalization when the CHA2DS2-VASc score was 1 or higher, but for all-cause mortality, the difference was only significant if the CHA2DS2-VASc score was 1 to 3, according to the researchers.
“Our study suggests that further research should be done to reevaluate the net clinical benefit of oral anticoagulants to prevent ischemic stroke in patients with [atrial flutter] according to the currently recommended level of the CHA2DS2-VASc score,” Lin and colleagues wrote. – by Erik Swain
Disclosure: The authors report no relevant financial disclosures.