Table 1.

Baseline characteristics of the study population (n=809)

CharacteristicMean ± SD or n
General
 Age (yr)55±10
 Female sex320 (39.6%)
 Incomea
  <$15,000/yr392 (48.5%)
  ≥$15,000/yr264 (32.6%)
 Prior cardiovascular disease428 (52.9%)
 Smoking
  Current240 (29.7%)
  Past234 (28.9%)
  Never335 (41.4%)
 Body mass index (kg/m2)30.4±6.5
 Categories of body mass index (kg/m2)
  <25.0169 (20.9%)
  25.0–29.9264 (32.6%)
  30.0–34.9198 (24.5%)
  ≥35.0178 (22.0%)
 Serum albumin (mg/dl)4.1±0.3
Kidney function
 125I-iothalamate GFR (ml/min per 1.73 m2)45.2±17.9
 Stage of CKDa
  2 (GFR≥60 ml/min per 1.73 m2)172 (21.3%)
  3a (GFR=45–59 ml/min per 1.73 m2)239 (29.5%)
  3b (GFR=30–44 ml/min per 1.73 m2)216 (26.7%)
  4–5 (GFR<30 ml/min per 1.73 m2)179 (22.1%)
 125I-iothalamate GFR slope (ml/min per 1.73 m2 per yr)b−1.55±2.20
 UPCRc0.07 (0.03, 0.32)
 Categories of UPCRa
  <0.22553 (68.4%)
  0.22–0.99146 (18.1%)
  ≥1.0084 (10.4%)
Mineral metabolites
 Serum FGF23 (pg/ml)c44.2 (30.7, 64.3)
  Elevated (>50 pg/ml)332 (41.0%)
 Intact PTH (pg/ml)c37 (24, 61)
  Elevated (>65 pg/ml)177 (21.9%)
 Serum phosphate (mg/dl)3.5±0.7
  Elevated (>4.6 mg/dl)38 (4.7%)
 25-hydroxyvitamin D (ng/ml)c13.4 (9.0, 19.2)
  Insufficient (<30 ng/ml)766 (94.7%)
  Deficient (<10 ng/ml)266 (32.9%)
 Serum calcium (mg/dl)8.9±0.5
Medication use
 25-hydroxyvitamin D4 (0.5%)
 Active vitamin D sterols6 (0.7%)
 Phosphate binding medications25 (3.1%)
  • a Total does not sum to 100% because of missing data.

  • b Estimated from month 3 to 12 postrandomization using linear mixed models.

  • c Presented as median (interquartile range).