Maintaining Normal Levels of Ionized Calcium during Citrate-Based Renal Replacement Therapy Is Associated with Stable Parathyroid Hormone Levels

Mario Raimundo, Siobhan Crichton, Katie Lei, Barnaby Sanderson, John Smith, John Brooks, Josephine Ng, Joanna Lemmich Smith, Catherine McKenzie, Richard Beale, Helen Dickie, Marlies Ostermann*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

Background/Aims: Citrate is an effective anticoagulant during continuous renal replacement therapy (CRRT). Previous studies showed raised parathyroid hormone (PTH) levels when aiming for serum ionized calcium [Ca-i] between 0.8 and 1.1 mmol/l. Our objective was to assess whether citrate-based CRRT with physiologic target systemic [Ca-i] between 1.12 and 1.20 mmol/l could maintain stable PTH levels. Methods: Measurement of intact PTH (PTHi) in 30 consecutive critically ill patients treated with citrate-based CRRT. Results: Thirty patients [mean age: 70.4 (SD 11.3) years; 56.7% males] were enrolled. Mean serum [Ca-i] was 1.16 mmol/l (SD 0.09), 1.13 mmol/l (SD 0.09), 1.17 mmol/l (SD 0.05) and 1.16 mmol/l (SD 0.04) at baseline, 12, 24 and 48 h, respectively (p = 0.29). Median PTHi levels (interquartile range) at baseline, 12, 24 and 48 h were 66.5 (43-111), 109 (59.5-151.5), 88.5 (47-133) and 85 pg/ml (53-140), respectively. The differences between baseline and 12 h and across all time points were statistically not significant (p = 0.16 and p = 0.49, respectively). In a mixed-effects model, each 0.1 mmol/l increase in serum [Ca-i] was associated with a 31.2% decrease in PTHi (p <0.001). Results were unchanged after adjustment for age, gender, magnesium, phosphate, arterial pH and time spent on CRRT. Conclusions: Maintaining systemic [Ca-i] within the physiologic range was associated with stable PTHi levels.

Original languageEnglish
Pages (from-to)124-131
Number of pages8
JournalNEPHRON CLINICAL PRACTICE
Volume124
Issue number1-2
DOIs
Publication statusPublished - Dec 2013

Keywords

  • Citrate
  • Parathyroid hormone
  • Continuous renal replacement therapy
  • Acute kidney injury
  • CRITICALLY-ILL PATIENTS
  • CONTINUOUS VENOVENOUS HEMOFILTRATION
  • HEPARIN ANTICOAGULATION
  • REGIONAL CITRATE
  • BONE-RESORPTION
  • HEMODIAFILTRATION
  • SECRETION
  • SEVERITY
  • SURVIVAL

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