Markers of vascular disease do not differ in black and white hemodialysis patients despite a different risk profile

Abstract

Increased aortic stiffness, as measured by pulse wave velocity (PWV) and augmentation index (Aix), and vascular calcification have been associated with an unfavourable cardiovascular outcome in hemodialysis patients. However, the majority of data have been published in white patients and epidemiological data are discordant on the fate of patients of different races. In this cross sectional study we measured PWV and Aix by applanation tonometry and coronary artery and thoracic aorta calcium score (CAC and AoC) by electron beam tomography (EBT) in 81 Blacks and 61 Whites on maintenance hemodialysis. Vascular stiffness measurements and EBT scans were performed within a week of each other. There was no difference between races in age, systolic blood pressure or gender distribution. Blacks had a more frequent history of hypertension (100% versus 89%; P = 0.002), lower prevalence of dyslipidemia (30% versus 66%; P < 0.001), higher PTH levels (geometric mean 607 pg/ml versus 245 pg/ml; P = 0.039), received calcium based phosphate binders less frequently (37% versus 60%, P = 0.007) and calcium antagonists more frequently than Whites (54% versus 28%; P = 0.003). Nonetheless, the unadjusted and risk adjusted PWV and Aix, as well as CAC and AoC were not statistically different between races. In this dialysis cohort there was no difference in markers of vasculopathy between black and white patients despite differences in baseline clinical characteristics. Epidemiological data from the general population indicate that Blacks have lower calcium scores and stiffer vessels than Whites. Some studies in the renal populations suggest a better and others a similar survival of Blacks and Whites on hemodialysis. Our findings raise the important question of the prognostic significance of markers of vasculopathy in patients of different races and with different risk profiles.