title: Renal osteodystrophy in predialysis and hemodialysis patients: comparison of histologic patterns and diagnostic predictivity of intact PTH.
abstract: BACKGROUND
  Comparison of renal osteodystrophy in predialysis and hemodialysis has been rarely reported. Distinct patterns of renal osteodystrophy could be found in these conditions. In addition the use of parathyroid hormone (PTH) and other markers for noninvasive diagnosis may result in different predictive values in predialysis and hemodialysis patients.
  
  
  METHODS
  79 consecutive patients with conservative chronic renal failure and 107 patients on hemodialysis were studied. All patients were subjected to bone biopsy for histological and histomorphometric evaluation. The patients had no exposure to aluminium before dialysis and relatively low exposure while on hemodialysis.
  
  
  RESULTS
  In the predialysis patients, bone biopsies showed 9 cases of adynamic bone disease (ABD) and 8 cases of osteomalacia (OM), 50 patients with mixed osteodystrophy and 2 cases of hyperparathyroidism. Among the hemodialysis patients 12 cases had ABD, 3 cases OM, 30 mixed osteodystrophy, and 61 patients hyperparathyroidism. In the predialysis patients with chronic renal failure, bone aluminium was on average 4.5 mg/kg dry weight, while in dialysis patients the average value was 35.4 mg/kg dry weight. Discriminant analysis of low turnover osteodystrophy (ABD and OM) by intact PTH showed higher accuracy in dialysis than in predialysis patients. Correlation studies of intact PTH versus bone formation rate, osteoblast surface/bone surface and osteoclast surface/bone surface showed significantly steeper slopes in dialysis than in predialysis patients, which indicates that bone resistance to PTH is more marked in predialysis patients.
  
  
  CONCLUSIONS
  The prevalence of ABD and OM in the geographic area investigated is lower than in other reports. Aluminium exposure does not seem to be the cause of low turnover osteodystrophy in the present population. The predictive value of intact PTH in the noninvasive diagnosis of renal bone disease is higher in hemodialysis patients than in predialysis patients. Predialysis chronic renal failure, when compared to the dialysis stage, seems to be characterized by resistance of bone tissue to PTH.
authors.affiliation: Pathophysiology and Hypertension Unit, Department of Nephrology, Second Medical Faculty, Rome, Italy. coen.gf@flashnet.it
authors.forename: Giorgio
authors.initials: G
authors.lastname: Coen
authors.forename: Paola
authors.initials: P
authors.lastname: Ballanti
authors.forename: Ermano
authors.initials: E
authors.lastname: Bonucci
authors.forename: Santo
authors.initials: S
authors.lastname: Calabria
authors.forename: Sergio
authors.initials: S
authors.lastname: Costantini
authors.forename: Michele
authors.initials: M
authors.lastname: Ferrannini
authors.forename: Marco
authors.initials: M
authors.lastname: Giustini
authors.forename: Rosa
authors.initials: R
authors.lastname: Giordano
authors.forename: Giulia
authors.initials: G
authors.lastname: Nicolai
authors.forename: Micaela
authors.initials: M
authors.lastname: Manni
authors.forename: Daniela
authors.initials: D
authors.lastname: Sardella
authors.forename: Franco
authors.initials: F
authors.lastname: Taggi
mesh_terms: D000328:Adult; D015415:Biomarkers; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology; D002118:Calcium / Q000097:blood; D012080:Chronic Kidney Disease-Mineral and Bone Disorder / Q000175:diagnosis* / Q000473:pathology*; D024042:Collagen Type I / Q000378:metabolism; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011237:Predictive Value of Tests; D006435:Renal Dialysis
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D002118:Calcium