Race is a major determinant of secondary hyperparathyroidism in uremic patients: comparative study of Blacks and Hispanics

BACKGROUND: Racial differences in bone and mineral metabolism are characterized by higher circulating intact parathyroid hormone levels (iPTH) in Black vs. White patients with end-stage renal disease (ESRD). The susceptibility of Hispanic patients to secondary hyperparathyroidism is not known. METHOD: This is a cross-sectional study that compares bone and mineral parameters of 48 Black and 61 Hispanic ESRD patients attending a single outpatient hemodialysis center. RESULT: The mean iPTH level was significantly higher in Blacks vs. Hispanics, despite similar levels of serum bone-specific alkaline phosphatase (BSAP), calcium, phosphorus and similar dosages of vitamin D analogs. After adjusting for independent variables including age, diabetic status and plasma levels of C-reactive protein, phosphorus and albumin significant predictors of iPTH were race (p < 0.01), gender (p < 0.05), serum calcium (p < 0.05), BSAP (p < 0.0001) and doses of vitamin D analogs (p < 0.001). Adjusted predictors of serum BSAP were PTH (p < 0.0001), gender (p = 0.01) and serum albumin (p < 0.005), but not race. There was no significant difference in serum BSAP between Blacks and Hispanics despite 60% higher iPTH levels in Blacks. CONCLUSIONS: Amongst ESRD patients, Blacks have higher iPTH levels compared with Hispanics despite similar BSAP levels, these finding support the emerging evidence of racial/ethnic differences in response of bone to PTH action.