Studies: Racial disparities in MI care might be provider-driven

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To add to the scores of studies that show racial disparities in healthcare, researchers in Michigan and California have found that black heart attack patients wait longer for advanced heart procedures compared with whites. However, these two studies concluded that these racial differences are not driven by race itself, but instead where the patients seek care.

In the first study published in the July issue of Medical Care, Colin R. Cooke, MD, a Robert Wood Johnson Foundation clinical scholar at the University of Michigan, and colleagues set out to better understand how hospitals influence racial differences in healthcare. To do so, Cooke and colleagues analyzed 25,847 Medicare records of patients who were admitted with acute MI (AMI) at nonrevascularization hospitals in 2006 and who were transferred to revascularization hospitals. Of the 25,847 patients, 42 percent were white and 37 percent were black. The patients were transferred from 857 urban hospitals and 774 rural non-revascularization hospitals and 928 revascularization hospitals.

The researchers reported that most elderly back patients within the study received care at hospitals that take longer to transfer patients, regardless of race. “These data suggest that an individual’s race may play much less of a role in generating differences in care, while the hospitals where black patients often go may be even more important,” Cooke said.

However, median length of stay was longer for black patients compared to white patients, two days versus one day. Black patients also had slower transfer times compared to white patients. Within urban hospitals, black patients were transferred an additional 0.24 days later than white patients. Length of stay for all patients prior to transfer at urban hospitals increased by 0.37 days for every 20 percent increase in the proportion of AMI patients who were black.

The researchers said that the causes for the delays in hospital transfer for hospitals that serve a greater number of black patients remain unknown, but speculated that quality of care at these hospitals may be worse.

“Strapped by financial constraints, safety net hospitals may forego development of a ‘quality improvement culture’ or limit adoption of computer order entry or electronic medical records, infrastructure which may improve the quality of care,” the authors wrote.

A second study published in the June 14 issue of Circulation showed similar results. In this study, Ioana Popescu, MD, of the David Geffen School of Medicine at the University of California, Los Angeles, and colleagues identified 65,633 Medicare patients with AMI in 63 hospital referral regions that had at least 50 black admissions during 2005. Of these patients, 87.4 percent were white and 12.6 percent were black.

To better understand racial disparities in healthcare, the researchers calculated the distance from patient home to hospital referral region hospitals using zip code centriods, and evaluated hospitals quality using hospital risk-adjusted 30-day mortality and AMI performance measures. Hospitals with a score in the top 20 percent were categorized as high quality and those that were in the lowest 20 percent were deemed low quality.

“Differences in admissions to revascularization and high-quality hospitals may contribute to disparities in AMI care,” the researchers found.

On average black patients lived closer to revascularization hospitals and high-quality hospitals compared to whites, 3.8 miles versus 6.8 miles and 5.6 miles versus 9.7 miles, respectively.

After adjusting for distance, the research showed that blacks were less likely to be admitted to revascularization hospitals and high-quality hospitals and were more likely to be admitted to low-quality hospitals.

The researchers said that a patient’s residence and a hospital’s availability of revascularization services were most influential. White patients were four times more likely to select hospitals closer to home compared with blacks who were only 2.6 times more likely to select the closest hospital. Whites were 3.5 times more likely to choose a revascularization hospital over those that don’t offer revascularization services, compared with black patients who were 2.6 times more likely to choose revascularization hospitals.

Lastly, the results showed that blacks were more likely than whites to choose teaching hospitals and both blacks and whites were less likely to select safety-net hospitals and for-profit hospitals.

“Black patients with AMI were relatively less likelyto select the closest hospital, hospitals providing coronary revascularization, and high-quality hospitals but relatively more likely to select low-quality hospitals, teaching hospitals and safety-net hospitals compared with white patients,” the authors wrote.

“The finding that black patients were relatively less likelythan white patients to be admitted to the closest hospital maybe significant in light of strong evidence that, at least in the case of ST-segment elevation MI, prompt coronary reperfusion improves survival after AMI.”

The researchers called the fact that racial differences in hospital admissions persisted even after accounting for distance to available hospitals “important,” and said that these racial differences could be due to unmeasured factors including transportation, differences in preference or perceived discrimination.

“The study confirms the role of differential access to hospitals with revascularization services and high quality of care as a plausible source of disparity. However, racial differences in access to high-quality hospitals appear to be primarily driven not by race in itself, but by differences in where the majority of blacks and whites live and seek care,” the authors concluded.

Authors of both studies concluded that policy leaders must focus on organizational issues and should take socioeconomic and healthcare system factors into consideration.