title: Hyperphosphatemia is a combined function of high serum PTH and high dietary protein intake in dialysis patients.
abstract: Elevated serum phosphorus is associated with higher death risk in hemodialysis patients. Previous studies have suggested that both higher serum parathyroid hormone (PTH) level and higher dietary protein intake may contribute to higher serum phosphorus levels. However, it is not well known how these two factors simultaneously contribute to the combined risk of hyperphosphatemia in real patient-care scenarios. We hypothesized that the likelihood of hyperphosphatemia increases across higher serum PTH and higher normalized protein catabolic rate (nPCR) levels, a surrogate of protein intake. Over an 8-year period (July 2001-June 2009), we identified 69,355 maintenance hemodialysis patients with PTH, nPCR, and phosphorus data in a large dialysis provider. Logistic regression models were examined to assess the association between likelihood of hyperphosphatemia (serum phosphorus >5.5 mg/dl) and serum PTH and nPCR increments. Patients were 61±15 years old and included 46% women, 33% blacks, and 57% diabetics. Both higher serum PTH level and higher protein intake were associated with higher risk of hyperphosphatemia in dialysis patients. Compared with patients with PTH level 150-<300 pg/ml and nPCR level 1.0-<1.2 g/kg/day, patients with iPTH>600 pg/ml and nPCR>1.2 g/kg/day had a threefold higher risk of hyperphosphatemia (OR: 3.17, 95% CI: 2.69-3.75). Hyperphosphatemia is associated with both higher dietary protein intake and higher serum PTH level in maintenance hemodialysis patients. Worsening or resistant hyperphosphatemia may be an under-appreciated consequence of secondary hyperparathyroidism independent of dietary phosphorus load. Management of hyperphosphatemia should include diligent correction of hyper-parathyroidism while maintaining adequate intake of high protein foods with low phosphorus content.
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine School of Medicine , Orange, California, USA.
authors.forename: Elani
authors.initials: E
authors.lastname: Streja
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine School of Medicine , Orange, California, USA.
authors.forename: Wei Ling
authors.initials: WL
authors.lastname: Lau
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine School of Medicine , Orange, California, USA.
authors.forename: Leanne
authors.initials: L
authors.lastname: Goldstein
authors.affiliation: Kaiser Permanente , Los Angeles, California, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Sim
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine School of Medicine , Orange, California, USA.
authors.forename: Miklos Z
authors.initials: MZ
authors.lastname: Molnar
authors.affiliation: DaVita , El Segundo, California, USA ; David Geffen School of Medicine at the University of California Los Angeles , Los Angeles, California, USA.
authors.forename: Allen R
authors.initials: AR
authors.lastname: Nissenson
authors.affiliation: University of Tennessee Health Science Center , Memphis, Tennessee, USA ; Memphis VA Medical Center , Memphis, Tennessee, USA.
authors.forename: Csaba P
authors.initials: CP
authors.lastname: Kovesdy
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology and Hypertension, University of California, Irvine School of Medicine , Orange, California, USA ; Department of Epidemiology, UCLA School of Public Health , Los Angeles, California, USA.
authors.forename: Kamyar
authors.initials: K
authors.lastname: Kalantar-Zadeh
keywords: chronic kidney disease (CKD); hemodialysis; hyperphosphatemia; parathyroid hormone; phosphorus; protein intake