NEW ORLEANS — Differential prophylactic aspirin use may contribute to racial disparities in stroke mortality, but does not appear to play a role in geographic disparities, according to findings from a cohort of patients in the ongoing Reasons for Geographic and Racial Differences in Stroke (REGARDS) study.
Nearly 17,000 adults, aged 45 years and older, participated in this segment of the REGARDS study, which included a computer-assisted telephone survey that inquired about patterns of prophylactic aspirin use, a follow-up home visit for a brief medical evaluation including blood pressure measurement and blood sampling within 2 weeks of the survey. Follow-up telephone interviews were conducted every 6 months thereafter regarding events and changes in cognitive function, Virginia Howard, M.S.P.H., explained at International Stroke Conference 2008, sponsored by the American Stroke Association.
Patients who self-reported a history of heart disease, stroke, or aspirin use for pain relief, and patients in whom aspirin use could not be determined, were excluded from the analysis.
Overall, about 31% of participants used aspirin prophylactically, with slightly higher rates in the “stroke belt” of the Southeastern United States, compared with the rest of the country. Oversampling was done in the stroke belt because of the higher stroke rates in that region, explained Ms. Howard of the department of epidemiology at the University of Alabama at Birmingham.
Men were significantly more likely than women to use aspirin prophylactically, and white participants were significantly more likely than blacks to use aspirin prophylactically (see box). There was also a trend toward increasing use with advancing age, she said.
Aspirin use also was higher among those with higher income levels and among those with the highest educational levels.
There was little difference in usage patterns at other educational levels, however. Additionally, aspirin use was higher among smokers, particularly past smokers, and in those with hypertension, diabetes, and/or dyslipidemia.
The investigators also analyzed aspirin dosages, comparing use of 75 mg with use of 325 mg. No geographic or age differences were noted in regard to dose, but the use of the lower dose was more common in white participants, women, and those with higher socioeconomic status. No differences in dose were noted according to risk factors.
Overall, “we found that prophylactic aspirin use was remarkably common in this cohort,” Ms. Howard said.
“Related to our primary goals, we did find that prophylactic aspirin use was higher among whites than African Americans, so this raises the possibility that this could be contributing to racial disparities in stroke mortality.”
However, counter to the investigators' hypothesis, the disparity in prophylactic aspirin use does not appear to contribute to the excess mortality in the stroke belt, as use was more common in that region compared with the rest of the nation, she said.
Ms. Howard noted that she had no financial conflicts of interest. However, the lead investigator for this portion of the REGARD study, Dr. Stephen P. Glasser who is also with the university, was a clinical site principal investigator for a previous trial sponsored by Bayer Healthcare.
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