CHADS2 Score for Stroke Risk Assessment in Atrial Fibrillation 

Updated: May 20, 2014
  • Author: Ethan Levine, DO; more...
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CHADS2 Score for Stroke Risk Assessment in Atrial Fibrillation

First published in 2001, the CHADS2 index (congestive heart failure, hypertension, age = 75 years, diabetes mellitus, stroke [doubled]) was developed to more accurately predict the risk of stroke in patients with nonvalvular atrial fibrillation. [1] The index was derived by combining risk factors from prior studies and then testing their validity in a cohort of 1773 Medicare-aged patients over 2121 patient years. [2, 3]

Table 1. CHADS2 Score: Stroke Risk Assessment in Atrial Fibrillation (Open Table in a new window)

Score CHADS2 Risk Criteria
1 point Congestive heart failure
1 point Hypertension
1 point Age >75 years
1 point Diabetes mellitus
2 points Stroke/transient ischemic attack

Table 2. Treatment Recommendations Based on CHADS2 Score (Open Table in a new window)

CHADS2 Score Risk Recommendation
0 Low Aspirin (81-325 mg) daily
1 Intermediate Aspirin (81-325 mg) daily or warfarin (INR 2.0–3.0), based on patient preference
2 or more High (CHADS2 revised) or intermediate (CHADS2 classic) Warfarin (INR 2.0-3.0), unless there are reasons to avoid it

Table 3. CHADS2 Score and Corresponding Annual Stroke Risk (Open Table in a new window)

CHADS2 Score Annual Stroke Risk, %
0 1.9
1 2.8
2 4
3 5.9
4 8.5
5 12.5
6 18.2

See also Medscape's Atrial Fibrillation CHADS2 Score for Stroke Risk calculator.