Racial Differences in Markers of Mineral Metabolism in Advanced Chronic Kidney Disease

• Published in: Clinical journal of the American Society of Nephrology Vol. 7; no. 4; pp. 640 - 647
• Main Authors: Jovanovich, Anna, Chonchol, Michel, Cheung, Alfred K., Kaufman, James S., Greene, Tom, Roberts, William L., Smits, Gerard, Kendrick, Jessica
• Format: Journal Article
• Language: English
• Published: United States American Society of Nephrology 01.04.2012
• Subjects: African Americans - statistics & numerical data; Aged; Biomarkers - blood; Bone and Bones - metabolism; Chi-Square Distribution; Chronic Disease; Cross-Sectional Studies; European Continental Ancestry Group - statistics & numerical data; Female; Fibroblast Growth Factors - blood; Humans; Kidney Diseases - blood; Kidney Diseases - ethnology; Kidney Diseases - therapy; Kidney Failure, Chronic - blood; Kidney Failure, Chronic - ethnology; Kidney Failure, Chronic - therapy; Linear Models; Male; Metabolic Diseases - blood; Metabolic Diseases - ethnology; Metabolic Diseases - therapy; Middle Aged; Multivariate Analysis; Original; Parathyroid Hormone - blood; Prospective Studies; United States - epidemiology; Vitamin D - analogs & derivatives; Vitamin D - blood
• ISSN: 1555-9041; 1555-905X; 1555-905X
• DOI: 10.2215/CJN.07020711

This study examined differences in the concentration of markers of mineral metabolism across race in patients with advanced CKD not requiring dialysis and ESRD. Concentrations of 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)(2)D), intact parathyroid hormone (iPTH), and fibroblast growth factor 23 (FGF-23) were measured in stored plasma samples of 1497 patients with advanced CKD not yet on dialysis and ESRD who participated in the Homocysteine in Kidney and End Stage Renal Disease study. Linear regression models were used to examine the relationship between race and 25(OH)D, 1,25(OH)(2)D, iPTH, and FGF-23 concentrations. Non-Hispanic white patients comprised 58% of the cohort, whereas non-Hispanic blacks comprised 42%. Median (interquartile range) FGF-23 concentrations were lower in blacks compared with whites with CKD (323 [181-655] versus 431 [232-1026] RU/ml; P<0.001) but not in ESRD. In adjusted linear regression models, blacks with CKD not requiring dialysis had significantly lower plasma FGF-23 concentrations (difference, -159; 95% confidence interval, -205 to -106; P<0.001) compared with whites, independent of plasma 25(OH)D, 1,25(OH)(2)D, and iPTH concentrations. This difference was not observed in the ESRD group. The magnitude of correlation for the relationships between 1,25(OH)(2)D with iPTH, FGF-23 with 1,25(OH)(2)D, and FGF-23 with iPTH were stronger among blacks than whites with CKD not requiring dialysis. In advanced CKD not requiring dialysis, blacks have lower FGF-23 concentrations than whites. Blacks with CKD and ESRD have lower 25(OH)D and higher iPTH compared with whites, independent of FGF-23 concentrations.