title: Parathyroid hormone may be an early predictor of low serum hemoglobin concentration in patients with not advanced stages of chronic kidney disease.
abstract: BACKGROUND
  Parathyroid hormone (PTH) has been associated with anemia only in dialysis patients with severe hyperparathyroidism. Whether an association between PTH and hemoglobin also exists in patients with chronic kidney disease not on dialysis (CKD-patients) is still unclear. In this study we evaluated the association between PTH and hemoglobin in CKD-patients without severe secondary hyperparathyroidism.
  
  
  METHODS
  Hospitalized patients and outpatients (N = 979) were retrospectively evaluated and categorized according to PTH quartile and serum hemoglobin (<12.0, <11.0, <10.0 g/dl). Gender, diabetes, glomerular filtration rate (GFR), hemoglobin, PTH, markers of mineral metabolism, inflammation, iron status and nutrition were variables of adjustment in univariate and multivariate analysis.
  
  
  RESULTS
  An inverse association (p = 0.001) was observed between PTH and hemoglobin in patients as a whole, in diabetics, and in patients with GFR ≤60 ml/min. PTH was the single predictor of low hemoglobin in patients as a whole (unstandardized beta -2.12; p = 0.005), in diabetics (unstandardized beta -8.86; p = 0.007) and in patients with GFR ≤60 ml/min (unstandardized beta -2.52; p = 0.006). For each increase of quartile of PTH the risk of having hemoglobin level <10.0 mg/dl was more than doubled [hazard ratio (HR) 2.79, 95% confidence interval (CI) 2.00-3.88; p = 0.001]. The receiver operating characteristic curve showed that PTH ≥122 pg/ml had 67% sensitivity and 75% specificity in predicting hemoglobin level <10.0 g/dl with area under the curve of 0.758 (95% CI 0.73-0.78).
  
  
  CONCLUSIONS
  This study shows a significant inverse association between PTH and hemoglobin levels across the whole spectrum of non-dialysis CKD and a doubled risk of having serum hemoglobin <10.0 mg/dl in the absence of severely deranged PTH concentration. These findings may have clinical relevance in ascertaining the cause of unexplained low hemoglobin levels in CKD-patients.
authors.affiliation: Department of Nephrology, University of Naples "FEDERICO II", Via S. Pansini, 5, 80131, Naples, Italy. domenicorusso51@hotmail.com.
authors.forename: Domenico
authors.initials: D
authors.lastname: Russo
authors.affiliation: Department of Nephrology, "G. RUMMO" Hospital, Benevento, Italy. lfmorrone@gmail.com.
authors.forename: Luigi
authors.initials: L
authors.lastname: Morrone
authors.affiliation: Department of Nephrology, "A. LANDOLFI" Hospital, Solofra, Avellino, Italy.
authors.forename: Biagio
authors.initials: B
authors.lastname: Di Iorio
authors.affiliation: Department of Health Sciences, University of Catanzaro, Catanzaro, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Andreucci
authors.affiliation: Department of Nephrology, University of Naples "FEDERICO II", Via S. Pansini, 5, 80131, Naples, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: De Gregorio
authors.affiliation: Department of Nephrology, University of Naples "FEDERICO II", Via S. Pansini, 5, 80131, Naples, Italy.
authors.forename: Carmela
authors.initials: C
authors.lastname: Errichiello
authors.affiliation: Department of Nephrology, University of Naples "FEDERICO II", Via S. Pansini, 5, 80131, Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Russo
authors.affiliation: Department of Nephrology, Alessandro Manzoni Hospital, Lecco, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Locatelli
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D005260:Female; D005919:Glomerular Filtration Rate; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011237:Predictive Value of Tests; D012372:ROC Curve; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000503:physiopathology; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D006454:Hemoglobins; D010281:Parathyroid Hormone
keywords: Anemia; Chronic kidney disease; Hemoglobin; Parathyroid hormone
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