Table 1.

Changes in markers of mineral metabolism with calcitriol and cholecalciferol administration

MetaboliteBaseline Concentration, Mean (SD)6-mo Change from Baseline, Estimate (95% CI)
CholecalciferolCalcitriolCholecalciferolCalcitriolDifference, Cholecalciferol − CalcitriolP Value for Difference
Total 25(OH)D, ng/ml22.7 (7.6)21.9 (7.8)11.7 (9.9 to 13.6)−0.8 (−2.7 to 1.0)12.6 (9.9 to 15.2)<0.001
 25(OH)D320.2 (8.7)18.6 (8.6)12.8 (11.0 to 14.6)0.1 (−1.7 to 1.9)12.7 (10.2 to 15.3)<0.001
 25(OH)D22.5 (4.6)3.2 (5.2)−1.2 (−1.9 to −0.4)−1.0 (−1.7 to −0.2)−0.2 (−1.3 to 0.9)0.74
24,25(OH)2D3, ng/ml1.6 (1.2)1.4 (1.0)1.4 (1.2 to 1.7)0.4 (0.1 to 0.6)1.1 (0.7 to 1.4)<0.001
Total 1,25(OH)2D, pg/ml28.9 (10.9)29.7 (11.2)−0.6 (−3.6 to 2.4)0.5 (−2.5 to 3.5)−1.1 (−5.3 to 3.1)0.62
 1,25(OH)2D326.0 (12.2)25.5 (11.4)1.1 (−1.8 to 4.1)3.1 (0.1 to 6.1)−2.0 (−6.2 to 2.2)0.35
 1,25(OH)2D22.9 (5.1)4.2 (8.1)−1.8 (−3.2 to −0.4)−2.6 (−4.0 to −1.2)0.9 (−1.1 to 2.9)0.39
24,25(OH)2D3-to-25(OH)D3 ratio, pg/ng73 (37)71 (37)17 (11 to 23)21 (14 to 27)−4 (−13 to 5)0.43
1,25(OH)2D3-to-25(OH)D3 ratio, pg/ng1.4 (0.7)1.6 (0.8)−0.5 (−0.8 to −0.3)0.2 (0.0 to 0.5)−0.8 (−1.1 to −0.4)<0.001
VDBG, μg/ml257 (45)255 (45)−4 (−15 to 6)−9 (−19 to 2)4 (−11 to 20)0.56
PTH, pg/ml140 (167)106 (65)−23 (−53 to 7)−27 (−57 to 3)4 (−38 to 47)0.84
iFGF-23, pg/ml121 (99)100 (60)58 (−36 to 151)176 (82 to 270)−118 (−251 to 15)0.08
  • Entries show baseline mean and SD for each marker by treatment group, the modeled difference in marker value comparing end of study with baseline marker value with 95% CIs, the modeled difference in marker change between cholecalciferol and calcitriol treatment groups, and the corresponding P value for the difference in change. All modeled estimates are derived from a linear mixed model with random intercepts and fixed effects of treatment group, time, and the treatment by time interaction. All randomized participants with any available vitamin D metabolites (n=128) were included in analysis. For the cholecalciferol group, measurements from n=62 and n=58 participants at baseline and 6 months, respectively, were included; for the calcitriol group, measurements from n=63 and n=56 participants at baseline and 6 months, respectively, were included. 95% CI, 95% confidence interval; 25(OH)D, 25-hydroxyvitamin D; 25(OH)D3, 25-hydroxyvitamin D3; 25(OH)D2, 25-hydroxyvitamin D2; 24,25(OH)2D3, 24,25-dihydroxyvitamin D3; 1,25(OH)2D, 1,25-dihydroxyvitamin D; 1,25(OH)2D3, 1,25-dihydroxyvitamin D3; 1,25(OH)2D2, 1,25-dihydroxyvitamin D2; VDBG, vitamin D binding globulin; PTH, parathyroid hormone; iFGF-23, intact fibroblast growth factor 23.