Vitamin D Binding Protein Is Not Involved in Vitamin D Deficiency in Patients with Chronic Kidney Disease
Table 2
Vitamin D and vitamin D binding protein in study groups.
Healthy controls (C)
Chronic kidney disease (CKD)
Long-term haemodialysis (HD)
Significance
25-OH vitamin D3 in plasma (ng/mL)
48.72 ± 18.35 47.10 (37.10–65.40)
30.16 ± 16.74 24.65 (19.45–38.50)
18.09 ± 15.64 13.70 (9.98–22.65)
< 0.0001 C versus CKD**** C versus HD**** CKD versus HD***
25-OH vitamin D2 in plasma (ng/mL)
Not detected
Not detected
Detected in 8 patients: 9.67 ± 7.80 8.08 (1.83–15.10)
Not evaluated
Total 25-OH vitamin D (D2 + D3) in plasma (ng/mL)
48.72 ± 18.35 47.10 (37.10–65.40)
30.16 ± 16.74 24.65 (19.45–38.50)
18.85 ± 15.85 14.45 (10.33–23.65)
< 0.0001 C versus CKD**** C versus HD**** CKD versus HD***
VDBP in serum (ug/mL)
222.0 ± 87.7 209.0 (163.0–269.2)
273.2 ± 93.8 268.0 (217.4–327.4)
213.8 ± 70.9 206.6 (161.5–252.3)
= 0.0003 C versus CKD* C versus HD n.s. CKD versus HD***
VDBP in urine (ug/mL)
Not assessed
0.25 ± 0.13 0.33 (0.12–0.35)
Not assessed
Not evaluated
25-OH vitamin D3/VDBP ratio (×10−6)
246.56 ± 112.44 242.54 (153.02–275.30)
129.72 ± 93.57 97.93 (72.34–191.86)
90.97 ± 74.97 70.84 (40.91–116.39)
< 0.0001 C versus CKD**** C versus HD**** CKD versus HD*
Total 25-OH vitamin D (D2 + D3)/VDBP ratio (×10−6)
246.56 ± 112.44 242.54 (153.02–275.30)
129.72 ± 93.57 97.93 (72.34–191.86)
95.26 ± 77.16 70.84 (42.23–120.172)
< 0.0001 C versus CKD**** C versus HD**** CKD versus HD n.s.
Results are expressed as mean ± standard deviation and in case of high interindividual variability also as medians (interquartile ranges). Comparison: one-way ANOVA and Tukey’s multiple comparison test. **** < 0.0001, *** < 0.001, and * < 0.05. VDBP: vitamin D binding protein.
