January 09, 2014
2 min read

Hospital quality linked to racial disparities in cardiac surgery

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A new analysis found that hospital quality is a major factor in racial disparities in mortality rates after CABG.

Previous research has shown that nonwhite patients have higher mortality rates after CABG compared with white patients, but the underlying mechanisms were not understood, researchers wrote in the study background.

Govind Rangrass, MD, of the University of Michigan, Ann Arbor, and colleagues reviewed the national Medicare database (2007-2008) to identify 173,925 patients (8.6% nonwhite) who underwent CABG. The goal was to determine whether hospital quality had an effect on racial disparities in mortality rates.

Compared with white patients, nonwhite patients were less likely to be male (nonwhites, 57.9%; whites, 69.5%), more likely to have hypertension (nonwhites, 69.8%; whites, 64%), more likely to have congestive HF (nonwhites, 25.6%; whites, 18.2%) and more likely to be admitted on an emergency basis (nonwhites, 30.1%; whites, 24.6%).

In unadjusted analysis, nonwhite patients had a higher risk for death after CABG than white patients (OR=1.33; 95% CI, 1.23-1.45). This did not change after controlling for patient factors (OR=1.33; 95% CI, 1.23-1.45).

For the study, hospitals were stratified by terciles according to the percentage of nonwhite patients undergoing CABG. The highest tercile of hospitals (treating >17.7% nonwhite patients) had the highest risk-adjusted mortality for both white (3.8%) and nonwhite (4.8%) patients, while the lowest tercile of hospitals (treating <2% nonwhite patients) had the lowest risk-adjusted mortality for both white (3.2%) and nonwhite (3.7%) patients, the researchers found.

The effect of race on mortality rates remained significant after adjustment for socioeconomic status only (OR=1.23; 95% CI, 1.13-1.34) or for hospital quality only (OR=1.22; 95% CI, 1.12-1.34), or for patient factors, socioeconomic status and hospital quality (OR=1.16; 95% CI, 1.05-1.27), according to the study results.

After evaluating the independent effects of each variable, Rangrass and colleagues estimated that 35% of the racial disparity in mortality rates was due to hospital variation, compared with 3% due to patient factors.

Fifty-three percent of the disparity can be explained by a combination of patient factors, socioeconomic status and hospital quality, but they the rest of the disparity remains unexplained, according to the researchers.

“Efforts to decrease racial disparities in health care should focus on underperforming centers of care treating disproportionately high numbers of nonwhite patients,” Rangrass and colleagues wrote. “Further research must also address geographic determinants of access to high-quality surgical care and the compounding effects of social segregation and entrenched referral patterns.”

Disclosure: The researchers report no relevant financial disclosures.