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CHADS₂ Score for Atrial Fibrillation Stroke Risk

CHADS₂ estimates annual stroke risk in non-valvular atrial fibrillation (0–6 points): CHF, hypertension, age ≥75, diabetes 1 point each; prior stroke/TIA 2 points. It has largely been replaced by CHA₂DS₂-VASc but still drives the Canadian CHADS-65 algorithm.

Age (years)
Congestive heart failure (yes/no, +1)
Hypertension (yes/no, +1)
Diabetes mellitus (yes/no, +1)
Prior stroke or TIA (yes/no, +2)

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Interpretation

Result	Meaning
0	Low risk (1.9%/yr)
1	Intermediate (2.8%/yr)
≥ 2	High (≥ 4.0%/yr)

Formula

C: CHF 1 · H: hypertension 1 · A: age ≥ 75 1 · D: diabetes 1 · S₂: prior stroke/TIA 2

Clinical pearls

CHADS₂ 0 does not mean no risk: use CHA₂DS₂-VASc (or CHADS-65 in Canada) to decide on anticoagulation.
Stroke rates are from the untreated NRAF cohort of Medicare patients and may overestimate risk in contemporary populations.

Examples

chads2 78 yo with htn and dm CHADS2 score for a 70 year old man with heart failure and prior TIA chads 2 score 82F htn chf dm prior stroke

FAQ

What is the difference between CHADS₂ and CHA₂DS₂-VASc?

CHA₂DS₂-VASc adds vascular disease, age 65–74 and female sex, and gives 2 points for age ≥75; it better identifies truly low-risk patients.

What stroke risk does each CHADS₂ score carry?

In the derivation cohort, adjusted stroke rates were 1.9, 2.8, 4.0, 5.9, 8.5, 12.5 and 18.2 per 100 patient-years for scores 0 to 6.

Evidence

Gage BF et al. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 2001;285:2864–70.

Cardiology · Reviewed 2026-10-14 · Methodology