Medicare beneficiaries who were referred to a primary stroke center after suffering a stroke had statistically significant lower seven-day and 30-day case fatality rates compared with those who were treated at local centers, according to a retrospective cohort study.

Lead researcher Kimon Bekelis, MD, of Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, and colleagues published their results online in JAMA Internal Medicine on July 25.

The Joint Commission, an independent, non-profit organization, certifies hospitals as being primary stroke centers if they meet certain requirements. The standards include designating a stroke unit for continuous patient monitoring, providing at least eight hours of stroke education each year to core stroke team members and complying with clinical practice guidelines set forth by the American Heart Association and American Stroke Association.

For this analysis, the researchers evaluated 865,184 Medicare beneficiaries who were admitted to a hospital with a stroke between Jan. 1, 2010, and Dec. 31, 2013. The mean age was 78.9 years old, and 55.5 percent of patients were females.

During the time period analyzed, there were 976 primary stroke centers, and 53.9 percent of patients in this study were treated in those locations. Patients admitted to primary stroke centers were more likely to receive intravenous tissue plasminogen activator and undergo mechanical thrombectomy, according to the researchers.

During the first seven days after hospital admission, 16.5 percent of patients hospitalized for in primary stroke centers died compared with 13.3 percent of patients hospitalized in non-primary stroke center hospitals. They 30-day death rates were 30.8 percent and 26.3 percent, respectively.

A multivariable regression analysis found that admission to a primary stroke center was associated with a 0.7 percent higher seven-day case fatality and 0.6 percent higher 30-day case fatality rate.

The researchers then adjusted for the time patients had to travel to hospitals. They found that 87.5 percent of patients were admitted to a primary stroke center if the primary stroke center was at least an hour closer than the nearest non-primary stroke center, while only 38.8 percent of patients were admitted to a primary stroke center when it was an hour farther from the non-primary stroke center.

After that adjustment, they said that primary stroke center admission was associated with a 1.8 percent reduction in seven-day case fatality and 1.8 percent decrease in 30-day care fatality.

Further, patients who traveled less than 90 minutes to a primary stroke center had a 30-day survival benefit, but those who traveled at least 90 minutes had no advantage.

The researchers mentioned a few potential limitations of the study, including coding inaccuracies, residual confounding and limiting the analysis to Medicare beneficiaries.

“Further investigations are necessary to identify the best combination of approaches to improve access to centers of excellence and stroke outcomes,” they wrote.