Hyperparathyroidism and dialysis vintage

BACKGROUND: Secondary hyperparathyroidism and its effects on bone and viscera are among the most important complications of end-stage renal disease. Despite its ubiquity, little is known about the treated natural history of the disorder. METHODS: We assembled a cohort of 310 patients with endstage renal disease on hemodialysis who were participants in one of four clinical trials of the phosphate binder sevelamer. Baseline parathyroid hormone levels were collected, and the relation between dialysis vintage and other clinical variables with parathyroid hormone were described. RESULTS: There was a direct relation between dialysis vintage and the severity of hyperparathyroidism. Other variables that were significantly associated with PTH on univariate analysis included age, African American race, Kt/V, and the serum concentrations of calcium, phosphate, and bicarbonate. Multivariable linear regression analysis yielded three significant predictors of PTH: calcium, phosphorus, and vintage (5.8% (4.0-7.5%) expected increase in PTH per year of vintage). The model R2 was 0.22. CONCLUSION: Dialysis vintage is a key determinant of the severity of secondary hyperparathyroidism. Vintage and certain laboratory variables should be considered in the evaluation of therapies aimed at modifying the treated natural history of this disorder.