Vitamin D Binding Protein and the Need for Vitamin D in Hemodialysis Patients

Speeckaert, Marijn M.; Glorieux, Griet L.; Vanholder, Raymond; Van Biesen, Wim; Taes, Youri E.; Clement, Frédéric; Wehlou, Charline; Delanghe, Joris R.

doi:10.1053/j.jrn.2008.04.013

« Previous Next »Journal of Renal Nutrition
Volume 18, Issue 5 , Pages 400-407, September 2008

Vitamin D Binding Protein and the Need for Vitamin D in Hemodialysis Patients

Marijn M. Speeckaert, MD
- Department of Clinical Chemistry, University of Ghent, Ghent University Hospital, Ghent, Belgium
Griet L. Glorieux, PhD
- Department of Nephrology, University of Ghent, Ghent University Hospital, Ghent, Belgium
Raymond Vanholder, MD, PhD
- Department of Nephrology, University of Ghent, Ghent University Hospital, Ghent, Belgium
Wim Van Biesen, MD, PhD
- Department of Nephrology, University of Ghent, Ghent University Hospital, Ghent, Belgium
Youri E. Taes, MD, PhD
- Department of Endocrinology, University of Ghent, Ghent University Hospital, Ghent, Belgium
Frédéric Clement, MT
- Department of Clinical Chemistry, University of Ghent, Ghent University Hospital, Ghent, Belgium
Charline Wehlou, MB, Ch B
- Department of Clinical Chemistry, University of Ghent, Ghent University Hospital, Ghent, Belgium
Joris R. Delanghe, MD, PhD
- Department of Clinical Chemistry, University of Ghent, Ghent University Hospital, Ghent, Belgium
- Address reprint requests to Joris R. Delanghe, MD, PhD, Department of Clinical Chemistry, University of Ghent, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium.

Objective

Vitamin D binding protein (DBP) is a polymorphic serum protein with a predominant role in a spectrum of biological activities. Chronic renal failure is characterized by deficient vitamin D metabolism. The present study investigates the impact of DBP polymorphism on the need for vitamin D in hemodialysis patients.

Design

This was a retrospective study.

Setting

This study included hemodialysis patients from the Renal Unit of Ghent University Hospital (Ghent, Belgium) and the Algemeen Stedelijk Ziekenhuis Geraardsbergen Hospital (Geraardsbergen, Belgium).

Methods

One hundred and ninety-one hemodialysis patients and 211 healthy subjects were recruited from the hemodialysis database. The DBP phenotypes were determined by polyacrylamide gel electrophoresis. Serum DBP, parathyroid hormone, 25-hydroxyvitamin D₃, 1,25-dihydroxyvitamin D₃, calcium, albumin, and phosphate were measured. Information regarding the intake of vitamin D analogues was collected.

Results

The phenotypic distributions of DBP were in agreement with Hardy-Weinberg equilibrium. Comparing allele frequencies of the two groups, there was an increased proportion of the DBP 2 allele in hemodialysis patients (P < .05). The median serum DBP concentration was lowest in the DBP 2-2 group. The need for oral vitamin D differed significantly (P < .01) between DBP phenotypes, and was greatest in DBP 2-2.

Conclusions

The present study demonstrates an altered DBP allele frequency in hemodialysis patients, compared with the general population. More importantly, vitamin D intake differs depending on the DBP polymorphism, and is greatest for end-stage renal disease patients with a DBP 2-2 phenotype. Therefore, vitamin D treatment deserves more careful monitoring among DBP 2-2 patients with end-stage renal disease.