With a Stroke Risk Score of 1—Do You Really Need an Anticoagulate?
Background readings: The CHADS2 & CHA2DS-VASc Stroke-Risk Grading Systems, and my 2015 AF Symposium reports: Dr. Hugh Calkins’ remarks on the AHA/ACC/HRS A-Fib Treatment Guidelines, and Dr. Peter Kowey’ talk, All Anticoagulants Cause Bleeding;
Current European guidelines for assessing A-Fib stroke risk state that a patient with a CHA2DS2-VASc score of 1 (on a scale of 0 to 10, no risk to high risk) should be taking novel oral anticoagulants (NOACs). But a recent Swedish study contradicts this.
A Swedish National Patient Registry study looked at 140,420 patients with A-Fib who had “stroke events”. For women with a score of 1, annual stroke rates varied between 0.1% and 0.2% (depending on which “event” definition was used). For men, the stroke rate varied between 0.5% and 0.7%.
The researchers stated, “These low annual event rates call into question the need for or use of oral anticoagulant therapy in these low-risk patients.”
Similar insights were found in a study of the National Health Insurance Research Database in Taiwan among 186,570 A-Fib patients not on antiplatelet or anticoagulant therapy. Researchers concluded that “not all risk factors in CHA2DS2-VASc score carry an equal risk.”
What this Means for A-Fib Patients
Taking an anticoagulant isn’t like taking vitamins. No one should be on anticoagulants unless they have an actual risk of stroke.
While the U.S. guidelines are an improvement over the European guidelines, based on the Swedish and Taiwan studies, neither the U.S. nor European guidelines recognize that someone with a score of 1 probably shouldn’t be on anticoagulants at all.
All anticoagulants cause bleeding (that’s how they work.) So they are inherently dangerous. Why run the risk if you don’t need to?
Taking an anticoagulant isn’t like taking a daily vitamin. No one should be on anticoagulants as a precaution, there should be an actual risk of stroke.
The Decision: To Take an Anticoagulant or Not?
When you have atrial fibrillation, whether or not to be on an anticoagulant to reduce your risk of stroke (and which one to take) is perhaps the most difficult decision for you and your doctor. That decision should be based on actual risk factors and not on a “precautionary” approach.
Remember, this decision means taking medication as long as you still have A-Fib. For some patients that’s a lifetime.