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Asian Americans Likely to Have More Severe Strokes

Asian-American stroke patients had more severe ischemic strokes, were less likely to receive intravenous tissue plasminogen activator (IV tPA), and had worse functional outcomes than white patients, a retrospective analysis showed.

They also had more hemorrhagic complications after receiving tPA, reported Sarah Song, MD, MPH, of Rush University Medical Center in Chicago, and colleagues in JAMA Neurology.

A study of of 64,337 Asian-American patients and 1,707,962 white patients admitted for acute ischemic stroke to hospitals participating in the Get With The Guidelines–Stroke (GWTG-Stroke) program from 2004 to 2016 showed that, after adjusting for patient and hospital variables, Asian Americans had:

  • Greater stroke severity than white patients: NIH Stroke Scale (NIHSS) score ≥16 (OR 1.35, 95% CI 1.30-1.40, P<0.001)
  • Higher in-hospital mortality (OR 1.14, 95% CI 1.09-1.19, P<0.001), longer length of stay (OR 1.17, 95% CI 1.14-1.20, P<0.001), and less independent ambulation at discharge (OR 0.84, 95% CI 0.79-0.90, P<0.001)
  • Fewer IV tPA administrations (OR 0.95, 95% CI 0.91-0.98, P=0.003), but more symptomatic hemorrhage after tPA (OR 1.36, 95% CI 1.20-1.55, P<0.001), and overall post-tPA complications (OR 1.31, 95% CI 1.18-1.46, P<0.001)

“This is just one study, but it’s alarming,” Song told MedPage Today. “Asian Americans are the most rapidly growing ethnic group in the country. This study is a call to action that we need more research in this population.”

The GWTG-Stroke program, originally designed to facilitate quality improvement activities at individual stroke centers, has grown collectively to offer insights into questions that clinical trials are not powered to answer, noted Cathy Sila, MD, of University Hospitals Cleveland Medical Center in Ohio, who was not involved with the analysis.

While the study also showed that Asian Americans were more likely to be on Medicaid, uninsured, and arrive at the hospital without utilizing pre-hospital providers, many questions about their outcomes remain unanswered, Sila observed. “Why did they fare more poorly? Once they came to the hospital, they received guidelines-driven care at excellent rates — across the board higher than whites — and had greater access to tPA,” she noted.

“But interestingly, this pattern of tPA access reversed when the data was adjusted for stroke severity,” Sila told MedPage Today. “Baseline stroke severity is the most powerful predictor of outcome and Asian Americans had a significantly higher mean NIHSS, as well as a greater proportion of severe strokes.”

“We know that the majority were cared for in the [western U.S.] (55.2% vs 17.6%), at academic centers, and less likely to be transferred, but to better interpret the findings, it would be helpful to know about the specific stroke subtypes and whether tPA was not given because other options were pursued, such as mechanical thrombectomy,” she continued.

Without knowing the type of cerebrovascular disease, differences in stroke mortality and complications can’t be fully understood, added Craig Anderson, MD, PhD, of the George Institute for Global Health at Peking University Health Science Center in Beijing, China, who also was not part of the study.

“Asians have more small vessel and intracranial atheroma than white Americans, who are likely to have more cardioembolic strokes,” he told MedPage Today. “These data also suggest Asian Americans are more at risk of the complications of thrombolysis, which may be due to dose calculation from estimated body weight,” he noted. Other studies have shown that lower doses of tPA in mainly Asian populations were not as effective but led to fewer intracranial hemorrhages.

Hospitals volunteer to be in the GWTG-Stroke program, and quality of stroke care may be higher than in nonparticipating hospitals, Song and colleagues noted. And at baseline, the Asian-American and white cohorts in this study had differences: the white group was older and was more likely to have specific vascular risk factors like atrial fibrillation and coronary artery disease, while the Asian-American group was more likely to have diabetes.

While Asian-American ethnicity in this study encompassed individuals from multiple heritages — Asian, Indian, Chinese, Filipino, Korean, Japanese, Vietnamese, and other groups — information about subgroups was not available. Other limitations of the study included potential residual confounding, which may account for some of the findings. In addition, small differences became statistically significant in this analysis because of the large sample size, possibly inflating the importance of differences between Asian-American and white patients, Song and colleagues added.

The GWTG-Stroke program is sponsored by the American Heart Association (AHA)/American Stroke Association. It is is sponsored in part by Medtronic and has been funded in the past through support from Boehringer-Ingelheim, Merck, a Bristol-Myers Squib/Sanofi Pharmaceuticals partnership, Janssen Pharmaceutical Companies of Johnson & Johnson, and the AHA Pharmaceutical Roundtable.

Song disclosed no relevant relationships with industry. Co-authors disclosed relevant relationships with Get With The Guidelines, the Patient Centered Outcome Research Institute, Janssen, Cardax, the Society of Cardiovascular Patient Care, TobeSoft, AHA, the Baim Institute for Clinical Research, Daiichi Sankyo, the Population Health Research Institute, the American College of Cardiology, Boehringer Ingelheim, Bayer, Abbott, Amarin, Amgen, AstraZeneca, Bayer, Bristol-Myers Squibb, Chiesi, Eisai, Ethicon, Forest Laboratories, Idorsia, Ironwood, Ischemix, Lilly, Medtronic, PhaseBio, Pfizer, Regeneron, Roche, Sanofi Aventis, Synaptic, The Medicines Company, Biotronik, Boston Scientific, Svelte, FlowCo, Merck, Novo Nordisk, PLx Pharma, Takeda, and Genentech.