CHADS2 score for risk of thromboembolism in atrial fibrillation

CHADS₂ score was developed to assess the risk of thromboembolism in non rheumatic atrial fibrillation. Scores were alloted to various risk factors as follows:

Congestive heart failure:    1
History of hypertension:    1
Age  > 75                    :    1
Diabetes                       :    1
Stroke / TIA                  :    2

Warfarin is indicated when CHADS₂ score is > 2

Ref: JAMA. 2001; 285:2864-70