Asian Americans are more likely to experience a severe ischemic stroke and have worse outcomes than whites despite improvements in care for both groups over the last dozen years, according to preliminary research reported at the International Stroke Conference in Los Angeles.

Using the national Get With the Guidelines-Stroke registry, researchers studied hospital admissions for 64,337 Asian-Americans and 1.7 million whites who suffered ischemic stroke from 2004 to 2016. They found 16.1 percent of Asian Americans had a National Institutes of Health Stroke Scale (NIHSS) score of 16 or higher. In comparison, 14.7 percent of whites experienced a stroke of that severity.

Adjusted odds of in-hospital mortality were 14 percent higher for Asian Americans, although when the severity of stroke was also factored in, Asian-Americans showed a 5 percent lower risk of in-hospital mortality. Asian Americans were also less likely to receive clot-busting tissue plasminogen activator (tPA) and experienced more serious complications from tPA (9.5 percent versus 7.9 percent), including for intracerebral hemorrhage (1.2 percent vs. 1.0 percent).

Over the course of the study, both groups showed a trend toward lower in-hospital mortality and receiving intravenous tPA.

“Looking from 2004 to 2016, our study shows that overall, patients with acute ischemic stroke are recovering more, and they are receiving more IV tPA, with less complications and better post-stroke care,” study coauthor Sarah Song, MD, PhD, MPH, said in a press release.

“This likely has to do with an overall improvement in stroke quality and highly effective stroke systems of care. However, Asian Americans and whites had nuanced differences over time; for example, only whites had a decrease in trend in stroke severity, while Asian Americans had a greater increase in timely IV tPA administration.”

Song acknowledged compiling all Asian Americans into a single group is problematic given the potential differences in risk factors, diet and lifestyle between various populations.

“But I do think this is a very good first step,” she said. “This information gives us the urgency and the credibility to do more research in Asian Americans, who have historically been understudied in the stroke and cardiovascular literature.”

American Stroke Association spokesperson Philip B. Gorelick, MD, MPH, agreed it is still difficult to assess the stroke outcomes among different Asian American populations but said, in general, hypertension has been a major challenge in Asia and is linked to higher stroke risk. He would like to see more investigation into the racial discrepancy in tPA-related administration and outcomes.

“More work needs to be done to improve clinical and functional outcomes in tPA administration in Asian American populations,” Gorelick said. “The study tends to show that that particular action was already ongoing in terms of quality as there were improvements over time but we still haven't hit the so-called sweet spot of defect-free care."