Assessing Stroke Risk: Understanding and Using the CHA₂DS₂-VASc Score

The original CHADS and CHADS-VASC scores demonstrate a significant correlation with the risk of developing stroke in patients with atrial fibrillation (AF), and have been included in the European Society of Cardiology (ESC) guidelines for the management and surveillance of AF patients. ^[1]

In a study involving over 100,000 patients:

• Aging was found to be strongly associated with an increased risk of stroke, particularly in patients over 75 years old (highest hazard ratio [HR] of 5.49, with an HR of 3.07 for patients aged 65-75) ^[3].
• Other significant risk factors for stroke included prior ischemic stroke (HR of 3.13), female gender (HR of 1.21), hypertension, diabetes mellitus (both with an HR of 1.19), and vascular disease (HR of 1.07) ^[3].
• Additionally, previous intracerebral hemorrhage (ICH) showed a high HR of 1.59 ^[3].

The incidence rate of ICH was 0.6 per 100 person-years, while major bleeding events occurred at a rate of 2.3 per 100 person-years of life ^[3].

Anti-thrombotic therapy did not influence the frequency of ICH or major bleeding. Other factors, such as female gender, myocardial infarction, vascular disease, diabetes, obesity, thyroid disease, and accidental falls, were also studied and did not show a significant influence on bleeding frequency ^[3].

Studies have indicated that each 1-point increase in the original CHADS2 score is associated with a 1.5 increase in the rate of stroke per 100 patient-years ^[2]. Furthermore, the new score has demonstrated an even stronger correlation with stroke risk in multiple studies ^[1][4].

According to a study, the overall ischemic stroke rate in non-anticoagulated AF patients was 3.20 per 100 person-years. The rates of thromboembolic events varied significantly based on conflicting treatment thresholds between European and U.S. guidelines. The European guideline recommends oral anticoagulant treatment for males with a CHA2DS2-VASc score of 1 or females with a score of 2, while the U.S. guideline offers a Class IIb recommendation for no treatment, aspirin therapy, or oral anticoagulant treatment for AF patients with a CHA2DS2-VASc score of 1 ^[3].

A study has shown that patients with heart failure and high CHADS-VASC scores tend to develop atrial fibrillation sooner ^[5]. This study also reported a slightly higher mortality rate, although the difference was statistically significant but not particularly large. Nonetheless, the study suggests that CHADS-VASC scores can serve as a useful tool not only for managing AF patients but also for predicting the probability of developing AF in selected patients, though further investigation is warranted ^[5].