Stroke risk drops in both black and white older adults

Recent reductions in hospitalization and death due to stroke extend to both black and white Medicare beneficiaries, reports a study in the April issue of Medical Care.

The reductions in mortality after initial stroke have been even greater in black Medicare patients, according to the new research by Margaret C. Fang, MD, MPH, of the University of California, San Francisco, and colleagues. Dr. Fang comments," Despite these promising trends, our study also found that black men and women continue to be at higher risk for stroke than white patients."

Stroke Risks Decline Over 25 Years—Trends Linked to Improving Risk Factors

Using Medicare data from 1988 to 2013, the researchers analyzed trends in hospitalization and mortality after an initial stroke in black or white men and women aged 65 or older. The study included more than 1 million hospitalizations for ischemic stroke, caused by blockage or narrowing of the brain blood vessels; and nearly 150,000 hospitalizations for hemorrhagic stroke, caused by bleeding into or around the brain.

Over the 25-year study period, hospitalizations for stroke decreased for both black and white patients. Adjusted for age, ischemic stroke risk decreased from 1,185 to 551 per 100,000 Medicare beneficiaries among black men and from 932 to 407 per 100,000 among white men. Risk fell from 1,222 to 641 per 100,000 for black women and from 892 to 466 per 100,000 for white women.

Mortality after ischemic stroke also fell, with greater reductions in black patients. Risk of death within 30 days after ischemic stroke decreased from approximately 16 to 8 percent in black men and from 16 to 12 percent in white men. Ischemic stroke mortality declined from about 14 to 9 percent in black women versus 16 to 15 percent in white women.

The data for hemorrhagic stroke showed a similar pattern: hospitalization rates decreased to a comparable extent in both races, while black patients had a greater reduction in mortality.

Although the study can't show a causal relationship, the reductions in stroke hospitalization and mortality were accompanied by declines in key risk factors: particularly smoking, blood pressure, and cholesterol levels. The improvements in stroke outcomes occurred despite the worsening US epidemic of diabetes and obesity.

The findings add to previous studies showing that stroke rates and stroke mortality have declined considerably over the past few decades. Along with reductions in the prevalence of stroke risk factors, these gains could potentially reflect improvements in stroke care, including the development of specialized stroke centers.

This study is important because black Americans have been shown consistently to be at higher stroke risk than whites. "Our study of evolving US trends in stroke found that both black and white Medicare enrollees experienced considerable improvements over time with regard to stroke hospitalizations,"  Dr. Fang and coauthors write.

Moreover, reductions in stroke mortality were more pronounced among blacks. Although the exact reasons for these observations could not be definitively established by the study, Dr. Fang states, "Our findings provide hopeful news about how stroke is being prevented and managed in the United States."