Working from medical records and a database of EKG records, the researchers identified 78,787 emergency patient visits, and 15,238 EKG results. Of those who had EKGs, 871 had AF, and full records were available for 866 of them. This gave the overall AF incidence rate of 1.1 percent.

Patients who had no previous AF diagnosis, or whose AF involved a heart valve, were not included in an analysis of medication patterns. A total of 478 individual patients with recurrent non-valvular AF, 63 of whom had more than one ER visit in the study period, were identified.

The mean age of the 478 patients was 74.5 years, meaning that many of the patients were at an increased risk of stroke not only from their AF but also from their age. Just over one-quarter of the patients had three high-risk factors for stroke.

Warfarin isn't for everyone, so Scott and his colleagues used strict standard guidelines to determine who was eligible for the drug and who wasn't, including those who had bleeding and liver problems, a history of falls or problems walking, or uncontrolled high blood pressure. A total of 240 patients weren't eligible for warfarin under these guidelines, and even some of the patients who were found to be on warfarin would have been ineligible under the guidelines.

Of the 291 patients who were eligible for warfarin, only 55 percent were on the drug. Another 22 percent were using antiplatelet drugs that can help slow clotting. But 23 percent were getting no stroke-prevention therapy at all. And of those who weren't eligible for warfarin but could take antiplatelet or aspirin therapy, only 34 percent were using any of the drugs.

The study also looked at the results of blood-clotting tests called INRs, to see if patien
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Contact: Kara Gavin
kegavin@umich.edu
734-764-2220
University of Michigan Health System
31-Oct-2002