The role of kidney transplantation and phosphate binder use in vitamin K status

Thijs T. Jansz*, Aegida Neradova, Adriana J. van Ballegooijen, Marianne C. Verhaar, Marc G. Vervloet, Leon J. Schurgers, Brigit C. van Jaarsveld

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background Cardiovascular disease is the leading cause of death in end-stage renal disease and is strongly associated with vascular calcification. Both kidney transplantation and phosphate binders may lower the risk of vascular calcification. Vascular calcification is actively inhibited by vitamin-K-dependent matrix y-carboxyglutamic acid protein (MGP). Whether kidney transplantation or phosphate binders affect vitamin K status is unknown. Therefore, we studied the influence of kidney transplantation and phosphate binder use on vitamin K status. Methods We measured plasma desphospho-uncarboxylated MGP (dp-ucMGP), a marker reflecting low vitamin K status, in a cross-sectional study of patients on hemodialysis (n = 82), peritoneal dialysis (n = 31) or who recently received a kidney transplantation (n = 36). By medication inventory, we assessed phosphate binder use. With linear regression, we assessed the influence of kidney transplantation and phosphate binder use on natural-log-transformed dp-ucMGP, adjusting for potential confounders. Results Mean age of patients was 52 +/- 13 years; 102 (68%) were male. Dp-ucMGP levels were significantly lower in kidney transplant recipients (median 689 pmol/L) compared to patients on dialysis (median 1537 pmol/L, p<0.001). Eighty-nine patients on dialysis used phosphate binders. Using any phosphate binder was not associated with dp-ucMGP levels (median 1637 pmol/L, p = 0.09) compared to no phosphate binders (median 1142 pmol/L). Twenty-six patients used sevelamer monotherapy, which was associated with higher dp-ucMGP levels (median 1740 pmol/L, p = 0.04) after adjusting for age, sex and vitamin K antagonist use. Conclusions Recent kidney transplantation is associated with lower dp-ucMGP levels suggesting improved vitamin K status after transplantation. Sevelamer monotherapy is associated with higher dp-ucMGP levels suggesting worsening of vitamin K status. Both findings warrant more attention to vitamin K status in patients on dialysis, as vitamin K is necessary for protection against vascular calcification.
Original languageEnglish
Article numbere0203157
Number of pages13
JournalPLOS ONE
Volume13
Issue number8
DOIs
Publication statusPublished - 30 Aug 2018

Keywords

  • MATRIX GLA-PROTEIN
  • STAGE RENAL-DISEASE
  • HEMODIALYSIS-PATIENTS
  • VASCULAR CALCIFICATION
  • MORTALITY
  • COHORT
  • SUPPLEMENTATION
  • SEVELAMER
  • SURVIVAL
  • IMPACT
  • Prospective Studies
  • Cross-Sectional Studies
  • Humans
  • Middle Aged
  • Extracellular Matrix Proteins/blood
  • Chelating Agents/adverse effects
  • Male
  • Kidney Transplantation
  • Kidney Failure, Chronic/blood
  • Female
  • Sevelamer/adverse effects
  • Calcium-Binding Proteins/blood
  • Renal Dialysis
  • Vitamin K/antagonists & inhibitors

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