Hospital quality tied to racial disparity in post-CABG deaths

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Nonwhite patients are more likely to die after CABG than white patients, and this disparity may be due in part to blacks’ poorer access to high-quality hospitals, a study published online Jan. 8 in JAMA Surgery found. Other unexplained factors may also contribute to the racial differences.

Govind Rangrass, MD, of the University of Michigan in Ann Arbor, and colleagues reviewed data from all CABG procedures performed in the U.S. between 2007 and 2008 using a Medicare database. They used these data to conduct analyses adjusted for risk and hospital quality and compared CABG mortality rates for whites and nonwhites in order to evaluate how socioeconomic status, hospital quality and hospital-specific patient factors played a role in the surgical outcome disparity. 

They broke down hospitals into equal-sized terciles based on the proportion of nonwhite patients who underwent CABG surgery. They also calculated socioeconomic status scores based on zip codes. The primary outcome was death within 30 days of CABG or in-hospital death.

Post-CABG mortality rates were 33 percent higher for nonwhites compared with whites. Mortality rates were higher in hospitals treating the most nonwhites (4.8 percent vs. 3.8 percent).

Further analysis found that 35 percent of the racial disparity was attributable to differences in hospital quality. After adjusting for differences in socioeconomic status and hospital quality, the researchers were able to account for 53 percent of the disparity between whites and nonwhites, 66 percent of the disparity between blacks and whites and 73 percent of the difference between Hispanics and whites.

But even after this analysis, the mortality rate for nonwhites was still 16 percent higher.

Other factors that could have contributed to the disparity included closeness to a high-quality hospital, differences in referral patterns and regional differences in hospital quality. However, the role of these factors is still unclear.

“Racial disparities in surgical outcomes represent a significant problem in our health care system,” the authors wrote. “Insight into how lower-quality hospitals widen disparities and gaps in patient care has important policy implications.”