CHADS₂

Stroke risk in non-valvular atrial fibrillation — original score
Congestive heart failure
Hypertension
Age ≥ 75 years
Diabetes mellitus
Prior stroke or TIA (2 points)
Evidence
Original publication
Gage BF, Waterman AD, Shannon W, et al. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. Defined CHADS₂ (CHF, hypertension, age ≥ 75, diabetes — 1 point each; prior stroke/TIA — 2 points); adjusted stroke rate rose from 1.9 to 18.2 per 100 patient-years across scores 0–6.
JAMA, 2001
Open source
Guideline
Current AF guidelines (2023 ACC/AHA/ACCP/HRS, 2020 ESC) use the CHA₂DS₂-VASc refinement to guide anticoagulation; CHADS₂ remains in wide use and in older trial evidence. This tool reports the original NRAF adjusted rates.
Last reviewed: 2026-09
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