Table 4: CHADS2 score quantification of stroke risk for patients with atrial fibrillation. NRAF: National Registry of Atrial Fibrillation. From [25].

CHADS2 scoreNo. of patients ( 𝑛 = 1 7 3 3 )No. of stroke ( 𝑛 = 9 4 )NRAF crude stroke rate per 100 patient-yearsNRAF adjusted stroke rate (95% CI)

012021.21.9 (1.2 to 3.0)
1463172.82.8 (2.0 to 3.8)
2523233.64.0 (3.1 to 5.1)
3337256.45.9 (4.6 to 7.3)
4220198.08.5 (6.3 to 11.1)
56567.712.5 (8.2 to 17.5)
65244.018.2 (10.5 to 27.4)