REPLY
Stroke Prevention Guidelines
David B. Matchar
1 February 1995 | Volume 122 Issue 3 | Pages 235-236
IN RESPONSE:
Recent clinical trials, including SPAF, have shown that anticoagulation with warfarin sodium can reduce the risk for stroke in patients with atrial fibrillation. As stated in our review, this relative risk reduction may not be worth the risks attendant to anticoagulation in patients in whom the absolute risk is small [1].
The crucial question is, who has a small absolute risk? The answer has been, and continues to be, a moving target. Indeed, since the submission of our manuscript, a pooled analysis by the Atrial Fibrillation Investigators has shown that persons with lone atrial fibrillation had a relatively low risk for stroke at any age [2]. One caveat is that these data were derived not from a population-based survey but rather from the experience of volunteers in a clinical trial. The risk for stroke in a more representative population of older persons with lone atrial fibrillation could be considerably higher.
Despite this caveat, we agree that the recent results support recommendations for using anticoagulation to treat atrial fibrillation less on the basis of age than on that of clinical characteristics. We look forward to the eventual validation of echocardiographic risk factors (not available to the Atrial Fibrillation Investigators) so that clinicians can better identify persons who can postpone or avoid anticoagulation.
1. Matchar DB, McCrory DC, Barnett HJ, Feussner JR. Medical treatment for stroke prevention. Ann Intern Med. 1994; 121:41-53.
2. Atrial Fibrillation Investigators. Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation: analysis of pooled data from five randomized controlled trials. Arch Intern Med. 1994; 154:1449-57.
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