title: Association of serum phosphorus level with anemia in kidney transplant recipients.
abstract: BACKGROUND
  Anemia and mineral and bone disorders (MBD) are both important and common complications in kidney transplant recipients. Studies in patients with chronic kidney disease indicated a possible independent association of higher serum phosphorus with anemia, but similar associations have not been examined in kidney transplant recipients. We hypothesized that higher serum phosphorus is associated with anemia independent of other components of MBD.
  
  
  METHODS
  We examined the association of serum phosphorus with hemoglobin level and the prevalence of anemia in a prevalent cohort of 992 kidney transplant recipients in a single outpatient transplant center. Associations were examined in linear and logistic regression models with adjustment for demographic and comorbid conditions for various known risk factors of anemia, including measures of iron deficiency, inflammation, and components of MBD including serum levels of 25(OH) vitamin D, parathyroid hormone, and fibroblast growth factor 23.
  
  
  RESULTS
  In multivariable adjusted regression models, a 1 standard deviation (0.8 mg/dL) higher serum phosphorus level was associated with 0.26 g/dL lower blood hemoglobin concentration (95% confidence intervals -0.36 to -0.15, P<0.001) and with an odds ratio for anemia of 1.77 (95% confidence intervals 1.33-2.37, P<0.001). These associations were consistent across the entire spectrum of the physiologic serum phosphorus concentration and were more accentuated in patients with lower estimated glomerular filtration rate.
  
  
  CONCLUSIONS
  Higher serum phosphorus is independently associated with anemia in kidney transplant recipients.
authors.affiliation: Division of Nephrology, Salem Veterans Affairs Medical Center, Salem, VA 24153, USA. csaba.kovesdy@va.gov
authors.forename: Csaba P
authors.initials: CP
authors.lastname: Kovesdy
authors.forename: Istvan
authors.initials: I
authors.lastname: Mucsi
authors.forename: Maria E
authors.initials: ME
authors.lastname: Czira
authors.forename: Anna
authors.initials: A
authors.lastname: Rudas
authors.forename: Akos
authors.initials: A
authors.lastname: Ujszaszi
authors.forename: Laszlo
authors.initials: L
authors.lastname: Rosivall
authors.forename: S Joseph
authors.initials: SJ
authors.lastname: Kim
authors.forename: Myles
authors.initials: M
authors.lastname: Wolf
authors.forename: Miklos Z
authors.initials: MZ
authors.lastname: Molnar
mesh_terms: D000328:Adult; D000368:Aged; D000740:Anemia / Q000097:blood / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D015536:Down-Regulation; D005260:Female; D005919:Glomerular Filtration Rate; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D006814:Hungary / Q000453:epidemiology; D016030:Kidney Transplantation / Q000009:adverse effects*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010045:Outpatients; D010758:Phosphorus / Q000097:blood*; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D010758:Phosphorus