Intact PTH Combined With the PTH Ratio for Diagnosis of Bone Turnover in Dialysis Patients: A Diagnostic Test Study

Johann Herberth, Adam J. Branscum, Hanna Mawad, Tom Cantor, Marie Claude Monier-Faugere, Hartmut H. Malluche

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Background: Determination of parathyroid hormone (PTH) level is the most commonly used surrogate marker for bone turnover in patients with stage 5 chronic kidney disease on dialysis therapy (CKD-5D). The objective of this study is to evaluate the predictive value of various PTH measurements for identifying low or high bone turnover rate. Study Design: Diagnostic test study. Settings & Participants: 141 patients with CKD-5D from 15 US hemodialysis centers. Index Tests: Intact PTH, PTH 1-84, and PTH ratio (ratio of level of PTH 1-84 to level of large carboxy-terminal PTH fragments). Reference Test or Outcome: Bone turnover determined using bone histomorphometry. Other Measurements: Demographic and treatment-related factors, serum calcium and phosphorus. Results: Patients presented histologically with a broad range of bone turnover abnormalities. In white patients with CKD-5D (n = 70), PTH ratio <1.0 added to intact PTH level <420 pg/mL increased the positive predictive value for low bone turnover from 74% to 90%. In black patients (n = 71), adding PTH ratio <1.2 to intact PTH level <340 pg/mL increased the positive predictive value for low bone turnover from 48% to 90%. Adding PTH ratio >1.6 to intact PTH level of 340-790 pg/mL increased the positive predictive value for high bone turnover from 56% to 71%. Limitations: Because the research protocol called for carefully controlled blood specimen handling, blood drawing and routine specimen handling might be less stringent in clinical practice. By limiting study participation to black and white patients with CKD-5D, we cannot comment on the roles of intact PTH, PTH 1-84, and PTH ratio in other racial/ethnic groups. Conclusion: In black patients with CKD-5D, the addition of PTH ratio to intact PTH measurements is helpful for diagnosing low and high bone turnover. In white patients with CKD-5D, it aids in the diagnosis of low bone turnover.

Original languageEnglish
Pages (from-to)897-906
Number of pages10
JournalAmerican Journal of Kidney Diseases
Volume55
Issue number5
DOIs
StatePublished - May 2010

Bibliographical note

Funding Information:
Support: The study was supported by the Dean's Clinical Research Scholar Program, University of Kentucky grant 1012112710 (Dr Herberth), National Institutes of Health grant RO1 DK51530 (Dr Malluche), and funding from the Kentucky Nephrology Research Trust (Dr Monier-Faugere).

Keywords

  • Intact parathyroid hormone (PTH)
  • PTH 1-84
  • PTH ratio
  • bone biopsy
  • bone turnover
  • chronic kidney disease
  • classification and regression tree (CART) analysis
  • dialysis
  • predictive value

ASJC Scopus subject areas

  • Nephrology

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