title: Uncorrected and Albumin-Corrected Calcium, Phosphorus, and Mortality in Patients Undergoing Maintenance Dialysis.
abstract: Uncorrected serum calcium concentration is the first mineral metabolism metric planned for use as a quality measure in the United States ESRD population. Few studies in patients undergoing either peritoneal dialysis (PD) or hemodialysis (HD) have assessed the association of uncorrected serum calcium concentration with clinical outcomes. We obtained data from 129,076 patients on dialysis (PD, 10,066; HD, 119,010) treated in DaVita, Inc. facilities between July 1, 2001, and June 30, 2006. After adjustment for potential confounders, uncorrected serum calcium <8.5 and ≥10.2 mg/dl were associated with excess mortality in patients on PD or HD (comparison group uncorrected calcium 9.0 to <9.5 mg/dl). Additional adjustment for serum albumin concentration substantially attenuated the all-cause mortality hazard ratios (HRs) associated with uncorrected calcium <8.5 mg/dl (HR, 1.29; 95% confidence interval [95% CI], 1.16 to 1.44 for PD; HR, 1.17; 95% CI, 1.13 to 1.20 for HD) and amplified the HRs associated with calcium ≥10.2 mg/dl (HR, 1.65; 95% CI, 1.42 to 1.91 for PD; HR, 1.59; 95% CI, 1.53 to 1.65 for HD). Albumin-corrected calcium ≥10.2 mg/dl and serum phosphorus ≥6.4 mg/dl were also associated with increased risk for death, irrespective of dialysis modality. In summary, in a large nationally representative cohort of patients on dialysis, abnormalities in markers of mineral metabolism, particularly high concentrations of serum calcium and phosphorus, were associated with increased mortality risk. Additional studies are needed to investigate whether control of hypercalcemia and hyperphosphatemia in patients undergoing dialysis results in improved clinical outcomes.
authors.affiliation: Kidney Research Institute, University of Washington, Seattle, Washington; mbr@uw.edu.
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Rivara
authors.affiliation: Harold Simmons Center for Chronic Disease Research and Epidemiology, University of California Irvine Medical Center, Irvine, California;
authors.forename: Vanessa
authors.initials: V
authors.lastname: Ravel
authors.affiliation: Harold Simmons Center for Chronic Disease Research and Epidemiology, University of California Irvine Medical Center, Irvine, California; Division of Nephrology and Hypertension, University of California Irvine Medical Center, Orange, California;
authors.forename: Kamyar
authors.initials: K
authors.lastname: Kalantar-Zadeh
authors.affiliation: Harold Simmons Center for Chronic Disease Research and Epidemiology, University of California Irvine Medical Center, Irvine, California; Fielding School of Public Health, University of California Los Angeles, Los Angeles, California;
authors.forename: Elani
authors.initials: E
authors.lastname: Streja
authors.affiliation: Division of Nephrology and Hypertension, University of California Irvine Medical Center, Orange, California;
authors.forename: Wei Ling
authors.initials: WL
authors.lastname: Lau
authors.affiliation: Division of Nephrology, Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California; and DaVita, Inc., El Segundo, California.
authors.forename: Allen R
authors.initials: AR
authors.lastname: Nissenson
authors.affiliation: Kidney Research Institute, University of Washington, Seattle, Washington;
authors.forename: Bryan
authors.initials: B
authors.lastname: Kestenbaum
authors.affiliation: Kidney Research Institute, University of Washington, Seattle, Washington;
authors.forename: Ian H
authors.initials: IH
authors.lastname: de Boer
authors.affiliation: Kidney Research Institute, University of Washington, Seattle, Washington;
authors.forename: Jonathan
authors.initials: J
authors.lastname: Himmelfarb
authors.affiliation: Kidney Research Institute, University of Washington, Seattle, Washington;
authors.forename: Rajnish
authors.initials: R
authors.lastname: Mehrotra
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002423:Cause of Death; D016208:Databases, Factual; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000175:diagnosis / Q000401:mortality*; D054559:Hyperphosphatemia / Q000175:diagnosis / Q000401:mortality*; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000379:methods / Q000401:mortality*; D011237:Predictive Value of Tests; D006435:Renal Dialysis / Q000379:methods / Q000401:mortality*; D012189:Retrospective Studies; D018570:Risk Assessment; D012709:Serum Albumin / Q000032:analysis*; D016019:Survival Analysis; D014481:United States
chemical_list: D015415:Biomarkers; D012709:Serum Albumin
keywords: ESRD; calcium; hemodialysis; mineral metabolism; mortality risk; peritoneal dialysis