Evidence-based On-call

Atrial fibrillation

Prevention

For patients at low-risk of stroke (<1% per year), at high-risk for a major bleed, or who particularly dislike the thought of taking warfarin ^a

give aspirin ^a

See anticoagulation chapter for more details on calculating your patient's risk of bleeding.

Why?

Aspirin reduces stroke compared with placebo without clearly increasing the risk of major haemorrhage. ^a
Aspirin is more cost-effective than warfarin for low-risk elderly patients or patients at high-risk of major haemorrhage ^a
Let patients who are at low or medium risk for stroke, make the choice - it is more cost-effective, than giving all patients warfarin. ^a

Aspirin reduces stroke compared with placebo

Patient	Treatment	Comparison	Outcome	CER	OR (95% CI)	NNT (95% CI)
AF ^a	aspirin	placebo	stroke at 1.6 years	13%	0.78 (0.62 to 0.98)	39 (22 to 440)

Note:

In one decision analysis, a patient's risk of falling had no effect on treatment option determined on the basis of the risk of bleeding or stroke. ^a