title: Serum phosphorus and association with anemia among a large diverse population with and without chronic kidney disease.
abstract: We hypothesized that phosphorus has an effect on anemia in both normal kidney function and early chronic kidney disease (CKD). We sought to determine whether higher phosphorus levels are associated with anemia in a large diverse population without CKD and early CKD.
  
  
  
  This study is a historical population-based study within the Kaiser Permanente Southern California health system (1 January 1998 to 31 December 2013) among individuals aged 18 years and older with estimated glomerular filtration rate >30 mL/min/1.73 m(2) and measurements of serum phosphorus, creatinine and hemoglobin. Individuals were excluded if they had secondary causes of anemia. Odds ratio (OR) estimated for moderate anemia defined as hemoglobin <11 g/dL for both sexes. Mild anemia was defined as <12 g/dL (females) and <13 g/dL (males).
  
  
  
  Among 155 974 individuals, 4.1% had moderate anemia and 12.9% had mild anemia. Serum phosphorus levels ≥3.5 mg/dL were associated with both mild and moderate anemia. Moderate anemia OR (95% confidence interval) was 1.16 (1.04-1.29) for every 0.5 mg/dL phosphorus increase and 1.26 (1.07-1.48) in the highest versus middle phosphorus tertile. Additional independent anemia risk factors, including female sex, Asian race, diabetes, low albumin and low iron saturation, were observed, but did not alter the anemia-phosphorus association.
  
  
  
  Higher phosphorus levels were associated with a greater likelihood for anemia in a population with early CKD and normal kidney function. Phosphorus may be a biomarker for anemia and may affect aspects of hematopoiesis.
authors.affiliation: Division of Nephrology and Hypertension, Kaiser Permanente Los Angeles Medical Center, Los Angeles, CA, USA.
authors.forename: Lac
authors.initials: L
authors.lastname: Tran
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Batech
authors.affiliation: Division of Nephrology and Hypertension, University of California Irvine School of Medicine, University of California Irvine Medical Center, Irvine, CA, USA.
authors.forename: Connie M
authors.initials: CM
authors.lastname: Rhee
authors.affiliation: Division of Nephrology and Hypertension, University of California Irvine School of Medicine, University of California Irvine Medical Center, Irvine, CA, USA.
authors.forename: Elani
authors.initials: E
authors.lastname: Streja
authors.affiliation: Division of Nephrology and Hypertension, University of California Irvine School of Medicine, University of California Irvine Medical Center, Irvine, CA, USA.
authors.forename: Kamyar
authors.initials: K
authors.lastname: Kalantar-Zadeh
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Jacobsen
authors.affiliation: Division of Nephrology and Hypertension, Kaiser Permanente Los Angeles Medical Center, Los Angeles, CA, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Sim
mesh_terms: D000740:Anemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010758:Phosphorus / Q000097:blood*; D051436:Renal Insufficiency, Chronic / Q000150:complications* / Q000503:physiopathology; D012307:Risk Factors
chemical_list: D006454:Hemoglobins; D010758:Phosphorus
keywords: anemia risk; epidemiology; serum phosphorus