Table 4.

Subgroup analysis: 6-month changes in primary and secondary outcomes by baseline vitamin 25(OH)D

Variable25(OH)D=10–30 ng/ml (Mild-to-Moderate Deficiency), n=6025(OH)D=31–100 ng/ml (Optimal Range), n=42
Placebo, n=17Treatment, n=43P ValueaPlacebo, n=18Treatment, n=24P Valuea
Primary outcome
 Pulse wave velocity, m/s0.3 (−1.1 to 1.6)0.2 (−0.6 to 1.1)0.971.1 (−0.5 to 2.7)−1.1 (−2.4 to 0.3)0.04
Secondary outcome
 Systolic BP, mmHg1.4 (−5.2 to 7.9)1.8 (−2.3 to 5.9)0.92−0.9 (−8.4 to 6.5)3.3 (−3.1 to 9.7)0.40
 Diastolic BP, mmHg2.1 (−1.7 to 6.0)1.3 (−1.2 to 3.7)0.701.6 (−2.6 to 5.8)0.9 (−2.7 to 4.6)0.81
 Urine ACR, ln(mg/g)−0.0 (−0.3 to 0.3)−0.0 (−0.2 to 0.2)0.940.2 (−0.1 to 0.5)−0.1 (−0.3 to 0.2)0.22
 Calcium, mg/dl−0.4 (−0.9 to 0.0)0.1 (−0.2 to 0.4)0.07−0.1 (−0.3 to 0.0)0.2 (0.0 to 0.3)0.003
 Phosphate, mg/dl0.2 (−0.1 to 0.5)0.1 (−0.1 to 0.3)0.640.2 (−0.1 to 0.4)0.3 (0.1 to 0.6)0.35
 PTH, ln(pg/ml)0.2 (−0.0 to 0.5)−0.3 (−0.5 to −0.2)0.0020.1 (−0.1 to 0.4)−0.4 (−0.6 to −0.2)<0.001
 FGF-23, ln(pg/ml)0.1 (−0.2 to 0.3)0.1 (−0.0 to 0.3)0.580.1 (−0.1 to 0.4)0.4 (0.2 to 0.6)0.12
 CRP, ln(mg/l)−0.1 (−0.4 to 0.3)−0.0 (−0.2 to 0.2)0.81−0.2 (−0.5 to 0.2)0.2 (−0.1 to 0.5)0.10
 Serum vitamin D
 25(OH)D, ng/ml1.9 (−19.9 to 23.7)31.8 (18.1 to 45.3)0.02−6.4 (−25.8 to 13.0)33.7 (17.1 to 50.4)0.003
 1,25(OH)2D, pg/ml2.1 (−2.1 to 6.2)4.2 (1.6 to 6.7)0.39−1.1 (−7.6 to 5.3)6.6 (0.9 to 12.3)0.08
  • Data are displayed as mean change and 95% CI. SI conversion factors: to convert urine ACR to mg/mmol, multiply by 0.113; to convert calcium to mmol/L, multiply by 0.25; to convert phosphate to mmol/L, multiply by 0.323; to convert PTH to pmol/L, multiply by 0.106; to convert 25(OH)D to nmol/L, multiply by 2.496; to convert 1,25(OH)2D to pmol/L, multiply by 2.6. 95% CI, 95% confidence interval; 25(OH)D, 25-hydroxyvitamin D; ACR, albumin-to-creatinine ratio; ln, natural logarithm; PTH, parathyroid hormone; FGF-23, fibroblast growth factor 23; CRP, C-reactive protein; 1,25(OH)2D, 1,25-dihydroxyvitamin D.

  • a Adjusted mean change, 95% CI, and P value for treatment effects, with the respective baseline value as covariate, compared using analysis of covariance.