To the Editor: Dr Klassen and colleagues¹ reported an association between pulse pressure and mortality among patients with end-stage renal disease (ESRD).

Although such patients often have abnormal mineral metabolism, Klassen et al do not fully address how their measure of calcium and phosphorus is related to mortality. In the multivariate analysis, levels of calcium, phosphorus, and parathyroid hormone (PTH) all had negative relationships with 1-year survival. These findings are of note since these variables have been shown to be associated with increased risk of vascular calcification and cardiovascular mortality.^2,3 Vascular calcification has been shown to contribute to the increased arterial stiffness seen in ESRD and is related to increased pulse wave velocity and pulse pressure.⁴ The finding by Klassen et al of increased cardiovascular mortality with increasing calcium, phosphorus, and PTH levels suggests a relationship, perhaps mediated by an osteoblastlike cell.⁵