The CHADS2 score: Stroke risk in atrial fibrillation [Classics Series]
CHADS₂ score calculator
The original stroke risk score for atrial fibrillation. Current guidelines use CHA₂DS₂-VASc.How the result reads
| Score | Stroke rate in the 2001 validation cohort |
|---|---|
| 0 | About 1.9 strokes per 100 patient-years without antithrombotic therapy. |
| 1 | About 2.8 strokes per 100 patient-years without antithrombotic therapy. |
| 2 | About 4.0 strokes per 100 patient-years without antithrombotic therapy. |
| 3 | About 5.9 strokes per 100 patient-years without antithrombotic therapy. |
| 4 | About 8.5 strokes per 100 patient-years without antithrombotic therapy. |
| 5 | About 12.5 strokes per 100 patient-years without antithrombotic therapy. |
| 6 | About 18.2 strokes per 100 patient-years without antithrombotic therapy. |
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The original study: Gage et al., 2001
Image: PD
1. The CHADS2 index is an accurate predictor of stroke in patients with non-rheumatic atrial fibrillation.
2. CHADS2 scores can be used to aid decisions regarding the need for anti-thrombotic therapy.
Original Date of Publication: June 13, 2001
Study Rundown: The CHADS2 index combined risk factors identified by the Atrial Fibrillation Investigators (AFI) and the Stroke Prevention and Atrial Fibrillation (SPAF) investigators to create a new clinical prediction model for stroke in patients with atrial fibrillation. This study validated the three tools and found that CHADS2 predicts stroke with greater accuracy than both the AFI and SPAF schemes. CHADS2 scores can be used to guide decisions regarding the need for anti-thrombotic therapy (i.e., aspirin for low-risk patients, warfarin for high-risk patients), particularly in identifying low-risk patients who may benefit from aspirin therapy. Strengths of the study include wide representation of regions within the United States and generalizability of results to frail, elderly patients. The CHADS2 index includes a limited set of risk factors for stroke and may neglect other important risk factors.
Please click to read the study in JAMA
In-Depth [randomized, controlled study]: This study, originally published in JAMA in 2001, evaluated the predictive accuracy of the AFI and SPAF stroke classification schemes, as well as the CHADS2 index, a new stroke-risk prediction model created by combining the AFI and SPAF schemes. CHADS2 is an acronym for the risk factors considered and their score value. One point is assigned for any of the following risk factors: recent congestive heart failure, hypertension, age ≥75 years, and diabetes mellitus. Two points were added if there is a history of stroke or transient ischemic attack.
|
Risk factor |
Points |
| Congestive heart failure |
1 |
| Hypertension |
1 |
| Age ≥75 years |
1 |
| Diabetes mellitus |
1 |
| Stroke or transient ischemic attack |
2 |
The study included 1,733 patients between ages 65 to 95 years with non-rheumatic atrial fibrillation. Stroke rate increased by a factor of 1.5 for each 1-point increment in CHADS2 score (P<0.001) and the CHADS2 index was found to predict stroke with greater accuracy than both the AFI and SPAF schemes with a c statistic of 0.82.
|
CHADS2 score |
Stroke rate per 100 patient-years |
|
0 |
1.9 |
|
1 |
2.8 |
|
2 |
4.0 |
|
3 |
5.9 |
|
4 |
8.5 |
|
5 |
12.5 |
|
6 |
18.2 |
By Adrienne Cheung, Andrew Cheung, M.D.
© 2013 2 Minute Medicine, Inc. All rights reserved. No part of this article may be reproduced, distributed or transmitted in any form or by any means without the prior written permission of 2 Minute Medicine, Inc. To license this content, contact 2 Minute Medicine, Inc. This article is for informational and educational purposes only; it is not medical advice and does not replace the judgment of a qualified healthcare professional.
Image: PD
Latest studies on the CHADS₂ score 2MM+
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