Ethnic differences in the relationship between albuminuria and calcified atherosclerotic plaque: the African American-diabetes heart study.

Abstract

Despite higher rates of nephropathy, calcified atherosclerotic plaque is less prevalent in African Americans with diabetes relative to European Americans. We explored ethnicity-specific relationships between albuminuria and calcified plaque involving the infrarenal aorta, coronary artery, and carotid artery in 835 European American and 393 African American subjects with type 2 diabetes. Generalized estimating equations with exchangeable correlation and the sandwich estimator of the variance were used to test for association between the principal component of calcified plaque in the three vascular beds and urine albumin-to-creatinine ratio (ACR). Mean +/- SD ages of African American and European American participants were 56.7 +/- 9.6 and 61.7 +/- 9.1 years, respectively, with diabetes duration of 10.4 +/- 7.4 and 10.0 +/- 7.3 years and median urine ACR of 17.5 and 13.4 mg/g. In African American and European American participants, respectively, median calcified plaque mass scores were 53.5 and 291 for coronary artery, 3 and 35.5 for carotid artery, and 761 and 3,237 for aorta. With adjustment for age, sex, glomerular filtration rate, and BMI, albuminuria was significantly associated with calcified plaque in European Americans (P = 3.4 x 10(-8)) but not in African Americans (P = 0.33), with significant ethnic interaction (P = 0.01). Ethnic differences in this relationship persisted after adjustment for blood pressure, smoking, lipids, and use of ACE inhibitors or angiotensin receptor blockers. Albuminuria is strongly associated with severity of calcified plaque in European Americans with diabetes but not in African Americans. Disparities in this relationship may contribute to ethnic differences in the rates of cardiovascular disease that are observed in subjects with type 2 diabetes.