Option 2 : Using CHADS2 Index
Stroke Risk in Patients With Nonvalvular AF Not Treated With Anticoagulation According to the CHADS2, Index

There are several stroke risk scores available and CHADS2 index is a simple and reasonable accurate for clinical use. Warfarin should be prescribed for the patient with CHADS2 score of 2 or higher.

CHADS2, Risk Criteria Score

Prior stroke or TIA
Age >75 y
Hypertension
Diabetes mellitus
Heart failure
2
1
1
1
1

Patients
(N=1723)

Adjusted Stroke Rate (%/y )*
(95% CI)

CHADS2 Score

Warfarin
(INR 2.0-3.0 )

120
463
523
337
220
65
5

1.9 (1.2 to 3.0)
2.8 (2.0 to 3.8)
4.0 (3.1 to 5.1)
5.9 (4.6 to 7.3)
8.5 (6.3 to 11.1)
12.5 (8.2 to 17.5)
18.2 (10.5 to 27.4)

0
1
2
3
4
5
6

.
.
Yes
Yes
Yes
Yes
Yes

Patients (N=1723)	Adjusted Stroke Rate (%/y )* (95% CI)	CHADS2 Score	Warfarin (INR 2.0-3.0 )
120 463 523 337 220 65 5	1.9 (1.2 to 3.0) 2.8 (2.0 to 3.8) 4.0 (3.1 to 5.1) 5.9 (4.6 to 7.3) 8.5 (6.3 to 11.1) 12.5 (8.2 to 17.5) 18.2 (10.5 to 27.4)	0 1 2 3 4 5 6	. . Yes Yes Yes Yes Yes

CHADS2, Risk Criteria	Score
Prior stroke or TIA Age >75 y Hypertension Diabetes mellitus Heart failure	2 1 1 1 1