Table 2.

Mineral metabolism biomarkers by CKD status before and after treatment

BiomarkerCKD (eGFR<60 ml/min per 1.73 m2)Non-CKD (eGFR≥60 ml/min per 1.73 m2)Difference in Change by CKD Status
BaselinePost-TreatmentChange (95% CI)P ValueBaselinePost-TreatmentChange (95% CI)P ValueDifference in Change (95% CI)P Value Interaction
25(OH)D total, ng/ml18.9 (1.8)41.1 (1.9)22.3 (18.3 to 26.2)<0.00120.4 (1.6)39.3 (1.6)18.9 (15.6 to 22.3)<0.0013.4 (−1.8 to 8.5)0.21
25(OH)D3, ng/ml16.9 (1.1)9.6 (1.2)−7.3 (−9.0 to −5.7)<0.00118.1 (1.0)9.2 (1.0)−8.9 (−10.3 to −7.5)<0.0011.6 (−0.6 to 3.7)0.15
25(OH)D2, ng/ml2.0 (1.5)31.7 (1.6)29.7 (25.7 to 33.6)<0.0012.3 (1.3)30.1 (1.3)27.8 (24.4 to 31.2)<0.0011.9 (−3.3 to 7.1)0.48
1,25(OH)2D total, pg/ml30.8 (2.5)34.2 (2.6)3.4 (−1.3 to 8.1)0.1548.4 (2.2)47.5 (2.2)−0.9 (−4.8 to 3.1)0.674.3 (−1.8 to 10.4)0.17
1,25(OH)2D3, pg/ml28.7 (2.2)9.9 (2.3)−18.8 (−23.8 to −13.7)<0.00145.6 (1.9)14.6 (1.9)−31.0 (−35.3 to −26.7)<0.00112.2 (5.6 to 18.9)<0.001
1,25(OH)2D2, pg/ml2.1 (1.6)24.4 (1.6)22.3 (18.2 to 26.4)<0.0012.8 (1.3)32.9 (1.4)30.1 (26.6 to 33.6)<0.001−7.8 (−13.2 to −2.4)0.01
24,25(OH)2D3, ng/ml1.3 (0.2)1.0 (0.2)−0.2 (−0.5 to −0.0)0.052.2 (0.2)1.7 (0.2)−0.5 (−0.7 to −0.3)<0.0010.3 (−0.1 to 0.6)0.10
PTH, pg/ml103.1 (9.2)94.6 (9.3)−8.6 (−20.3 to 3.1)0.1560.4 (8.0)50.6 (8.0)−9.8 (−19.7 to 0.1)0.051.2 (−14.1 to 16.5)0.88
FGF-23, pg/ml81.6 (6.1)83.6 (6.2)2.0 (−5.7 to 9.8)0.6147.0 (5.3)50.5 (5.3)3.4 (−3.1 to 10.0)0.30−1.4 (−11.6,8.7)0.78
Calcium, mg/dl8.9 (0.2)8.9 (0.2)0.0 (−0.3 to 0.4)0.868.7 (0.2)8.7 (0.2)−0.0 (−0.4 to 0.3)0.830.1 (−0.4 to 0.6)0.78
Phosphorus, mg/dl3.4 (0.2)3.6 (0.2)0.2 (−0.3 to 0.6)0.453.2 (0.2)3.5 (0.2)0.3 (−0.1 to 0.7)0.11−0.1 (−0.7 to 0.4)0.62
24,25(OH)2D3 to 25(OH)D3, pg/ng72.0 (9.1)110.3 (9.3)38.3 (20.9 to 55.7)<0.001115.7 (7.8)195.2 (7.9)79.5 (64.7 to 94.2)<0.001−41.2 (−64.0 to −18.3)<0.001
1,25(OH)2D3 to 25(OH)D3, pg/ng1.8 (0.2)1.1 (0.2)−0.7 (−1.2 to −0.3)0.0013.0 (0.2)1.7 (0.2)−1.3 (−1.7 to −0.9)<0.0010.6 (0.0 to 1.2)0.05
Vitamin D binding protein, μg/ml264.0 (7.0)253.8 (7.2)−10.1 (−22.1 to 1.8)0.10255.4 (6.1)260.8 (6.1)5.5 (−4.6 to 15.6)<0.001−15.6 (−31.2 to 0.0)0.05
Estimated bioavailable 25(OH)D2.2 (0.3)5.2 (0.3)2.9 (2.3 to 3.6)<0.0012.3 (0.3)4.4 (0.3)2.1 (1.5 to 2.7)<0.0010.8 (−0.0 to 1.7)0.06
  • Cell contents are mean (SD), mean change (95% CI), difference in mean changes (95% CI), P value within group, or P value for interaction comparing change among participants with CKD with change among participants without CKD. 95% CI, 95% confidence interval; 25(OH)D, 25-hydroxyvitamin D; 25(OH)D3, 25-hydroxyvitamin D3; 25(OH)D2, 25-hydroxyvitamin D2; 1,25(OH)2D, 1,25-dihydroxyvitamin D; 1,25(OH)2D2, 1,25-dihydroxyvitamin D2; 1,25(OH)2D3, 1,25-dihydroxyvitamin D3; 24,25(OH)2D3, 24,25-dihydroxyvitamin D3; PTH, parathyroid hormone; FGF-23, fibroblast growth factor-23.