title: Serum phosphate levels and mortality risk among people with chronic kidney disease.
abstract: Elevated serum phosphate levels have been linked with vascular calcification and mortality among dialysis patients. The relationship between phosphate and mortality has not been explored among patients with chronic kidney disease (CKD). A retrospective cohort study was conducted from eight Veterans Affairs' Medical Centers located in the Pacific Northwest. CKD was defined by two continuously abnormal outpatient serum creatinine measurements at least 6 mo apart between 1999 and 2002. Patients who received chronic dialysis, those with a present or previous renal transplant, and those without a recent phosphate measurement were excluded. The primary end point was all-cause mortality. Secondary end points were acute myocardial infarction and the combined end point of myocardial infarction plus death. A total of 95,619 veterans with at least one primary care or internal medicine clinic contact from a Northwest VA facility and two or more outpatient measurements of serum creatinine, at least 6 mo apart, between January 1, 1999, and December 31, 2002, were identified. From this eligible population, 7021 patients met our definition of CKD. After exclusions, 6730 CKD patients were available for analysis, and 3490 had a serum phosphate measurement during the previous 18 mo. After adjustment, serum phosphate levels >3.5 mg/dl were associated with a significantly increased risk for death. Mortality risk increased linearly with each subsequent 0.5-mg/dl increase in serum phosphate levels. Elevated serum phosphate levels were independently associated with increased mortality risk among this population of patients with CKD.
authors.affiliation: Veterans' Affairs Puget Sound Health Care System, Division of Nephrology, Mail Stop 111A, 1660 South Columbian Way, Seattle, WA 98108, USA. brk@u.washington.edu
authors.forename: Bryan
authors.initials: B
authors.lastname: Kestenbaum
authors.forename: Joshua N
authors.initials: JN
authors.lastname: Sampson
authors.forename: Kyle D
authors.initials: KD
authors.lastname: Rudser
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Patterson
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Seliger
authors.forename: Bessie
authors.initials: B
authors.lastname: Young
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Sherrard
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Andress
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D002130:Calcium Phosphates / Q000097:blood*; D002423:Cause of Death; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000009:adverse effects / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017678:Sex Distribution; D016019:Survival Analysis
chemical_list: D015415:Biomarkers; D002130:Calcium Phosphates