Significant drop in stroke recurrence found among Mexican Americans

The rate of recurrent strokes significantly declined among Mexican Americans in a long-term study, according to new research published today in Stroke, a journal of the American Stroke Association, a division of the American Heart Association.

Recurrent stroke rates declined faster in Mexican Americans than in non-Hispanics whites. By the end of the study in 2013, the differences between these two groups had vanished. Mexican Americans had a significant reduction in stroke recurrence even though the death rate from stroke remained steady.

"Throughout this long-term study, this is the first time that we have encountered an improvement in any major marker of ethnic stroke disparities," said Lewis Morgenstern, M.D., lead study author and professor of neurology and epidemiology at the University of Michigan's Medical School and School of Public Health in Ann Arbor, Michigan.

Mexican Americans make up 63% of the subpopulation of Hispanic Americans, which are the most numerous U.S. minority population. Currently, 9.2% of Hispanic Americans are older than 65, and, by 2040, this percentage is expected to climb to 15.8%. This population will have a substantial risk for stroke and stroke recurrence, making secondary stroke prevention extremely important.

The Brain Attack Surveillance in Corpus Christi (BASIC) project started in Jan. 1, 2000, and is an ongoing study focused on stroke surveillance. The study's 3,571 participants self-identified as Mexican Americans and non-Hispanic whites in Nueces County, Texas, and were from a predominantly non-immigrant population comprised almost entirely of second and third generation U.S. citizens. The participants were 56% Mexican American, at least 45 years old and 50% women. First-ever strokes occurred between Jan. 1, 2000, and Dec. 31, 2013. Records were cross-referenced with the Texas Department of Health death certificates and adjusted for age, sex, hypertension, diabetes, smoking, atrial fibrillation, insurance and cholesterol.

In this study, stroke was defined as a clot disrupting blood flow to the brain (ischemic) or bleeding in the brain (hemorrhagic). Cases were followed to determine one- and two-year stroke recurrence. Recurrent strokes were observed in 206 patients during the 1-year follow-up period, and 683 deaths occurred before any recurrence. In the 2-year follow-up, 293 recurrent strokes were observed, and 883 deaths occurred before another stroke.

Researchers found:

• among Mexican Americans, incidence of 1-year recurrence was 9.26% in 2000 and dropped to 3.42% in 2013;
• among non-Hispanic whites, the incidence of 1-year recurrence was 5.67% in 2000 and reduced to 3.59% in 2013; and
• the recurrence trend changes from 2000 through 2013 were significant among Mexican Americans but not among non-Hispanic whites.

"These results suggest that stroke recurrence continues to decline in both populations, but faster in Mexican Americans, perhaps because their rates were so high to begin with," Morgenstern said. "Individuals should work to reduce their chance of having a stroke by following national healthy living guidelines such as the American Heart Association's Life's Simple 7."

Although this is a community-based study with multiple efforts to ensure accuracy, it is still one community, and the results may not be generalizable, particularly to immigrant Hispanic populations. There is also a small chance that patients may have had a recurrent stroke during their initial hospitalization or after they left the community. The effects of sex differences were not analyzed in this study.

According to the American Stroke Association, the most common symptoms of stroke are known as F.A.S.T., face drooping, arm weakness, speech and time to call 9-1-1. Bystanders should call 911 for immediate medical attention even if the symptoms go away.