Dysregulated mineral metabolism in patients with acute kidney injury and risk of adverse outcomes

Clin Endocrinol (Oxf). 2013 Oct;79(4):491-8. doi: 10.1111/cen.12172. Epub 2013 Mar 26.

Abstract

Objective: Numerous studies have evaluated the prevalence and importance of vitamin D deficiency among patients with chronic kidney disease and end-stage renal disease; however, little is known about vitamin D levels in acute kidney injury (AKI). We evaluated the association between vitamin D metabolites and clinical outcomes among patients with AKI.

Design: Prospective cohort study.

Patients: A total of 30 participants with AKI and 30 controls from general hospital wards and intensive care units at a tertiary care hospital were recruited for the study.

Measurements: Plasma levels of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)2 D], 24R,25-dihydroxyvitamin D3 , vitamin D binding protein (VDBP) and fibroblast growth factor 23 (FGF23) were measured within 24 hours of AKI onset and 5 days later. Bioavailable 25(OH)D and 1,25(OH)2 D levels, defined as the sum of free- and albumin-bound 25(OH)D and 1,25(OH)2 D, were estimated using equations.

Results: Compared to controls, participants with AKI had lower levels of 1,25(OH)2 D [17 (10-22) vs 25 (15-35) pg/ml, P = 0·01], lower levels of VDBP [23 (15-31) vs 29 (25-36) mg/dl, P = 0·003] and similar levels of bioavailable 25(OH)D and 1,25(OH)2 D at enrolment. Levels of bioavailable 25(OH)D were inversely associated with severity of sepsis in the overall sample (P < 0·001). Among participants with AKI, bioavailable 25(OH)D, but not other vitamin D metabolites, was significantly associated with mortality after adjusting for age and serum creatinine (adjusted odds ratio per 1 SD ln [bioavailable 25(OH)D] = 0·16, 95% confidence interval = 0·03-0·85).

Conclusions: Bioavailable 25(OH)D could have a role as a biomarker or mediator of adverse outcomes among patients with established AKI.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 24,25-Dihydroxyvitamin D 3 / blood*
  • Acute Kidney Injury / blood*
  • Acute Kidney Injury / mortality
  • Biomarkers / blood
  • Female
  • Fibroblast Growth Factors / blood*
  • Hospitals, General
  • Humans
  • Intensive Care Units
  • Logistic Models
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Prospective Studies
  • Reference Values
  • Survival Rate
  • Tertiary Care Centers
  • Time Factors
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D-Binding Protein / blood*

Substances

  • Biomarkers
  • Vitamin D-Binding Protein
  • Vitamin D
  • 24,25-Dihydroxyvitamin D 3
  • Fibroblast Growth Factors
  • fibroblast growth factor 23
  • 25-hydroxyvitamin D