Recount the CHA2DS2-VASc before you act on it

Two of today's findings turn on a score being counted correctly, and it is counted wrongly more often than anyone admits. The commonest errors are consistent: adding a point for female sex and then treating a woman with a score of 1 as though she were at intermediate risk; scoring 2 for age 65 to 74 rather than 1; and missing vascular disease entirely, because prior myocardial infarction, peripheral artery disease and aortic plaque all count and none of them is asked about routinely.

The sequence worth fixing in your head is that female sex is a risk modifier, not a risk factor. A woman with no other risk factor has a score of 1 and the risk profile of a man with a score of 0. The intermediate-risk category that today's anticoagulation trial studied is a score of 1 in men and 2 in women — that is, exactly one genuine risk factor in either sex.

The practical habit: before recommending or withholding anticoagulation, say the components aloud — congestive heart failure, hypertension, age 75 or over for two, diabetes, prior stroke or transient ischaemic attack for two, vascular disease, age 65 to 74, female sex. Ask about vascular disease explicitly rather than assuming it would have been mentioned. Then decide.

• Female sex modifies risk rather than creating it; a woman scoring 1 on sex alone is not at intermediate risk
• Age 75 and over scores two points; age 65 to 74 scores one — a frequent slip
• Ask directly about prior myocardial infarction, peripheral artery disease and aortic plaque, all of which score
• Prior stroke or transient ischaemic attack scores two, not one
• Recalculate at each review — the score rises with age whether or not anything else changes

Read the rest in the app

You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.

Get Daily Doctor — free

Scan to keep reading on your phone. No account needed to start.