The impact of race/ethnicity on baseline characteristics and the burden of coronary atherosclerosis in the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial.

OBJECTIVES

We aimed to test the impact of race/ethnicity on coronary artery disease (CAD) after adjusting for baseline risk factors.

BACKGROUND

Whether race/ethnicity remains an important determinant of the burden of CAD even among patients with long-standing type 2 diabetes (diabetes mellitus) and established CAD is unknown.

METHODS

Analysis of baseline data from the BARI 2D trial (January 1, 2001, to March 31, 2005) was performed. Myocardial jeopardy index (MJI) was evaluated by a blinded core angiographic laboratory. Multivariate regression analysis was performed to determine the independent association of race/ethnicity on the burden of CAD after adjusting for baseline risk factors. Data were collected from US and Canadian academic and community hospitals. The baseline analysis was performed on patients with long-standing diabetes and documented CAD with no prior revascularization at study entry (n = 1,331). The main outcome measure was MJI, which represents the percentage of myocardium jeopardized by significant lesions (≥50%). The secondary outcome measure was ≥2 lesions with ≥50% stenosis.

RESULTS

Risk factors varied significantly among racial/ethnic groups. Blacks were significantly more likely to be women, have no health insurance, be current smokers, have higher body mass index, have hypertension, have a longer duration of diabetes, a higher hemoglobin A(1c) level, and were more likely to be taking insulin. Their mean total, low-density lipid, and high-density lipid cholesterol levels were higher, whereas their triglycerides were lower than others. After controlling for baseline risk factors, blacks had a significantly lower burden of CAD; the adjusted MJI was 5.43 U lower (95% CI -9.13 to -1.72), and the adjusted number of lesions was 0.53 fewer (95% CI -0.88 to -0.18) in blacks compared to whites.

CONCLUSIONS

In the BARI 2D trial, self-reported race/ethnicity is associated with important differences in baseline risk factors and is a powerful predictor of the burden of CAD adjusting for such baseline differences. These findings may help direct medical intervention and resources and further investigation into the basis of racial/ethnic differences in CAD burden.