In a real-world cohort of patients in Taiwan, patients with atrial fibrillation and at least one additional risk factor for stroke were at high risk for ischemic stroke and researchers recommended that oral anticoagulation be considered in this patient population.
The retrospective study included 12,935 men with AF and a CHA2DS2-VASc score of 1 and 7,900 women with AF and a CHA2DS2-VASc score of 2 aged 20 years and older in the National Health Insurance Research Database in Taiwan. No patients were receiving antiplatelet or anticoagulant treatment.
The primary endpoint was incidence of ischemic stroke. Mean follow-up was 5.2 ± 4.3 years.
“Although the CHA2DS2-VASc (congestive HF, hypertension, age 75 years or older, diabetes mellitus, previous stroke or transient ischemic attack, vascular disease, age 65 to 74 years, female) score is recommended by both American and European guidelines for stroke risk stratification in AF, the treatment recommendations for a CHA2DS2-VASc score of 1 are less clear,” the researchers wrote.
For men with AF, the most prevalent risk factor was older age (65 to 74 years). For women with AF, the most prevalent risk factor was hypertension.
Overall, ischemic stroke occurred in14.4% of men with a CHA2DS2-VASc score of 1 and 14.9% of women a CHA2DS2-VASc score of 2 during follow-up. The researchers calculated an annual stroke rate of 2.75% for men and 2.55% for women.
Analysis according to CHA2DS2-VASc score components demonstrated that risk for ischemic stroke among men ranged from 1.96% per year for those with vascular disease to 3.5% per year for those aged 65 to 74 years. Among women, the risk for ischemic stroke ranged from 1.91% per year for those with hypertension to 3.34% per year for those aged 65 to 74 years.
Men with a CHA2DS2-VASc score of 1 and hypertension had a significantly increased risk for ischemic stroke compared with men with a score of 0 (HR = 1.681; 95% CI, 1.333-2.12). A further increased risk was observed among men with a score of 1 who were aged 65 to 74 years (HR = 3.085; 95% CI, 2.79-3.41). Similar results were observed among women with a CHA2DS2-VASc score of 2 and hypertension compared with a score of 1 (HR = 1.711; 95% CI, 1.481-1.976), and among those aged 65 to 74 years (HR = 3.031; 95% CI, 2.678-3.431).
“[Oral anticoagulants] should be considered for AF patients with one additional stroke risk factor given their high risk of ischemic stroke,” the researchers wrote. “Future studies should attempt to define the net clinical benefit of anticoagulation, balancing the prevention of both thromboembolism and major bleeding, for patients with AF who have one stroke risk factor in addition to sex.”
In a related editorial, Hugh Calkins, MD, from the department of cardiology at Johns Hopkins Hospital, said the findings are “striking” and offer new information that supports recommending anticoagulation for all patients with AF except those at very low risk for stroke. However, he wrote, these results alone are not sufficient to warrant an update to current guidelines.
“Considering the safety and efficacy of antithrombotic therapy, it seems clear that we should think long and hard before recommending that patients with a CHA2DS2-VASc score of 1 not receive anticoagulant therapy,” Calkins wrote. – by Adam Taliercio
Disclosure: One researcher reports financial relationships with Astellas, Bayer, Biotronik, Boehringer Ingelheim, Bristol-Myers Squibb/Pfizer, Daiichi-Sankyo, Medtronic, Merck, Portola and Sanofi. Calkins reports consulting for AtriCure, Boehringer Ingelheim and Daiichi-Sankyo.