Table 1.
Changes in markers of mineral metabolism with calcitriol and cholecalciferol administration
| Metabolite | Baseline Concentration, Mean (SD) | 6-mo Change from Baseline, Estimate (95% CI) | ||||
|---|---|---|---|---|---|---|
| Cholecalciferol | Calcitriol | Cholecalciferol | Calcitriol | Difference, Cholecalciferol − Calcitriol | P Value for Difference | |
| Total 25(OH)D, ng/ml | 22.7 (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)D3 | 20.2 (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)D2 | 2.5 (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/ml | 1.6 (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/ml | 28.9 (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)2D3 | 26.0 (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)2D2 | 2.9 (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/ng | 73 (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/ng | 1.4 (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/ml | 257 (45) | 255 (45) | −4 (−15 to 6) | −9 (−19 to 2) | 4 (−11 to 20) | 0.56 |
| PTH, pg/ml | 140 (167) | 106 (65) | −23 (−53 to 7) | −27 (−57 to 3) | 4 (−38 to 47) | 0.84 |
| iFGF-23, pg/ml | 121 (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.