Hyperparathyroidism and dialysis vintage

<(Background)under bar>: Secondary hyperparathyroidism and its effects on b one and viscera are among the most important complications of end-stage ren al disease. Despite its ubiquity, little is known about the treated natural history of the disorder. <(Methods)under bar>: We assembled a cohort of 31 0 patients with endstage renal disease on hemodialysis who were participant s in one of four clinical trials of the phosphate binder sevelamer. Baselin e parathyroid hormone levels were collected, and the relation between dialy sis vintage and other clinical variables with parathyroid hormone were desc ribed. <(Results)under bar>: There was a direct relation between dialysis v intage and the severity of hyperparathyroidism. Other variables that were s ignificantly associated with PTH on univariate analysis included age, Afric an American race, Kt/V, and the serum concentrations of calcium, phosphate, and bicarbonate. Multivariable linear regression analysis yielded three si gnificant predictors of PTH: calcium, phosphorus, and vintage (5.8% (4.0 - 7.5%) expected increase in PTH per year of vintage). The model R-2 was 0.22 . <(Conclusion)under bar>: Dialysis vintage is a key determinant of the sev erity of secondary hyperparathyroidism. Vintage and certain laboratory vari ables should be considered in the evaluation of therapies aimed at modifyin g the treated natural history of this disorder.