CHA₂DS₂-VASc vs CHA₂DS₂-VA: what changed and why

The one difference: the sex category point

CHA₂DS₂-VASc and CHA₂DS₂-VA differ by a single item. CHA₂DS₂-VASc, published by Lip and colleagues in Chest in 2010, scores congestive heart failure, hypertension, diabetes, vascular disease and age 65 to 74 at 1 point each, age 75 or older and prior stroke, TIA or thromboembolism at 2 points each, and adds 1 point for female sex (the "Sc", sex category), for a range of 0 to 9. CHA₂DS₂-VA keeps every item and weight except the sex point, so it runs from 0 to 8. For a man the two scores are always identical. For a woman, CHA₂DS₂-VA is always exactly 1 point lower than CHA₂DS₂-VASc. The 2024 European Society of Cardiology (ESC) atrial fibrillation guideline adopted CHA₂DS₂-VA, describing female sex as an age-dependent stroke risk modifier rather than a risk factor on its own. The 2023 ACC/AHA/ACCP/HRS guideline still uses CHA₂DS₂-VASc.

How the thresholds line up

The ACC/AHA and ESC thresholds sort patients almost the same way once you account for the missing point. The 2023 ACC/AHA/ACCP/HRS guideline sets its bands one point higher for women: anticoagulation is recommended (Class 1) at a CHA₂DS₂-VASc of 2 or more in men and 3 or more in women, and is reasonable (Class 2a) at 1 in men and 2 in women. The 2024 ESC guideline uses one set of numbers for everyone: anticoagulation is recommended (Class I) at a CHA₂DS₂-VA of 2 or more and should be considered (Class IIa) at 1. Since a woman's CHA₂DS₂-VA is her CHA₂DS₂-VASc minus 1, a woman at 3 on CHA₂DS₂-VASc sits at 2 on CHA₂DS₂-VA, and a woman at 2 sits at 1. The practical gain is simpler arithmetic and one rule for all patients, not a different group of patients being treated.

Why the ESC dropped female sex

The ESC dropped the sex point for two reasons: female sex mainly adds risk on top of other risk factors, and a sex-neutral score works for every patient. Nielsen and colleagues tested this in Circulation in 2018 with Danish registries covering 239,671 patients with non-valvular AF diagnosed from 1997 to 2015, 48.7% of them women, followed off anticoagulation for up to a year. At a CHA₂DS₂-VA of 0, the 1-year risk of thromboembolism was 0.5% in both men and women. Only above 1 point did women show a higher risk than men with the same score, which led the authors to call female sex a risk modifier rather than a risk factor. They suggested that first decisions on anticoagulation could use CHA₂DS₂-VA, while the sex effect accentuates risk in women who already qualify through 2 or more other factors. The ESC also wanted one score for people who are non-binary, transgender or on sex hormone therapy, for whom a sex point is unclear.

Does CHA₂DS₂-VA predict stroke as well?

CHA₂DS₂-VA appears to predict stroke at least as well as CHA₂DS₂-VASc in recent data, though not in older cohorts. Teppo and colleagues compared the two in the Finnish FinACAF cohort, 144,879 patients with new AF from 2007 to 2018 who were not taking anticoagulants, half of them women; 3,936 (2.7%) had an ischemic stroke within a year. In 2007 to 2008, when women with AF had a higher stroke risk than men, CHA₂DS₂-VASc did better than CHA₂DS₂-VA on net reclassification. The gap narrowed every year, and by 2017 to 2018, when the sex difference in stroke risk had largely gone, CHA₂DS₂-VA was marginally better: its category-based net reclassification index turned positive at 0.070, and its discrimination edged ahead. The authors linked the change to falling stroke risk in women over time. Both scores still rank patients only moderately well, so neither gives a precise individual risk.

Worked example: the same patient on both scores

Take a 70-year-old woman with hypertension and no other risk factors. On CHA₂DS₂-VASc she scores 1 for age 65 to 74, 1 for hypertension and 1 for female sex, a total of 3: the high band under the 2023 ACC/AHA/ACCP/HRS guideline, where anticoagulation is recommended. On CHA₂DS₂-VA she scores 2, which is also the threshold for a Class I recommendation under the 2024 ESC guideline. Now take a 60-year-old woman with no risk factors at all. She scores 1 on CHA₂DS₂-VASc, the low band for a woman, and 0 on CHA₂DS₂-VA, the low band for everyone. A 60-year-old man with diabetes scores 1 on both, the intermediate band in either guideline. In each case the decision band is the same; only the number written in the notes differs. When you record a score, name which one you used, because a woman's two scores always differ by a point.

The CHA₂DS₂-VASc calculator shows both: the CHA₂DS₂-VASc total with the ACC/AHA band, and the CHA₂DS₂-VA score under the result.