Hyperphosphatemia in Dialysis Patients: Beyond Nonadherence to Diet and Binders

Abstract

Hyperphosphatemia in dialysis patients is routinely attributed to nonadherence to diet, prescribed phosphate binders, or both. The role of individual patient variability in other determinants of phosphate control is not widely recognized. In a manner that cannot be explained by dialysis parameters or serum phosphate levels, dialytic removal of phosphate may vary by >400mg per treatment. Similarly, enteral phosphate absorption, unexplained by diet or vitamin D intake, may differ by ≥250mg/d among patients. Binder efficacy also varies among patients, with 2-fold differences reported. One or more elements of this triple threat-varying dialytic removal, phosphate absorption, and phosphate binding-may account for hyperphosphatemia in dialysis patients rather than nonadherence to therapy. Just as the cause(s) of hyperphosphatemia may vary, so too may an individual patient's response to different therapeutic interventions.

Keywords: Hyperphosphatemia; binder efficacy; dialysis; dialytic phosphate removal; dietary phosphate; enteral phosphate absorption; individual variation; phosphate binders; phosphate levels; treatment adherence; vitamin D.