Researchers, including neurologists from the Mayo Clinic, say the findings could help explain why the black population of the United States has a higher incident of strokes and death from strokes than the white population.
The results were presented Friday at the American Heart Association's 2010 International Stroke Conference in San Antonio. It will be published in Stroke: Journal of the American Heart Association.
"The reasons for the racial discrepancy are not known," said Dr. James Meschia, Mayo Clinic neurologist and director of the Comprehensive Stroke Center at Mayo's campus in Florida. "But they are consistent with other studies that show blacks are less likely to receive the care they need to treat stroke risk factors such as diabetes and hypertension."
The study examined 30,239 men from 2003 to 2007. Atrial fibrillation was diagnosed using an electrocardiogram (ECG) test given to participants in their homes. Before the visit, participants were asked by telephone if a physician or a health professional had ever told them that they had atrial fibrillation, and they were also asked what medications they were using. While 60 percent of the total group (black and white) were aware of their diagnosis, the odds that blacks knew they had the condition were less than one-third of those reported for whites, researchers say.
They found that the odds of blacks being treated with warfarin, which reduces stroke risk by 60 percent, were one-fourth those of whites. In other words, blacks in this study with atrial fibrillation were two-thirds less likely to know they had the disorder and three-fourths less likely to be treated with warfarin, the standard of care.
Insurance status was not a factor in the racial disparity because the majority of study participants were over age 65 and were covered by Medicare.
"Whatever the reasons behind these observations, it appears that there is a missed opportunity to prevent stroke and other thromboembolic complications from atrial fibrillation because many individuals may fail to have the condition diagnosed and/or fail to receive treatment with warfarin," Meschia said. "It would benefit public health if future research could tease out the reasons behind this disparity."