Table 1. Baseline characteristics of patients at study enrollment stratified by iPTH levels.
| iPTH < 200 pg/mL | 200 ≤ iPTH < 300 pg/mL | 300 ≤ iPTH < 500 pg/mL | iPTH ≥ 500 pg/mL | P valuea | Overall | |
|---|---|---|---|---|---|---|
| Number of patients | 881 | 1,067 | 824 | 504 | - | 3,276 |
| Age (mean [SD]) | 62.7 (12.9) | 62.7 (12.6) | 61.5 (12.8) | 59.7 (11.9) | <0.001 | 61.9 (12.7) |
| Male (%) | 62.5 | 62.7 | 59.2 | 60.9 | 0.403 | 61.5 |
| Primary Disease (%) | <0.001 | |||||
| Chronic Glomerulonephritis | 42.1 | 40.8 | 45.1 | 57.9 | 44.9 | |
| Diabetic Nephropathy | 28.9 | 27.9 | 21.1 | 12.9 | 24.2 | |
| Dialysis vintage, years (median [IQR]) | 6.7 (2.9, 12.4) | 7.1 (3.1, 13.0) | 8.9 (4.2, 15.2) | 11.6 (7.4, 17.9) | <0.001 | 8.3 (3.7, 14.3) |
| BMI, kg/m2 (mean [SD]) | 21.3 (3.5) | 21.4 (3.6) | 21.5 (3.9) | 21.2 (3.4) | 0.647 | 21.4 (3.6) |
| Coronary Artery Disease (%) | 26.4 | 26.6 | 24.0 | 23.8 | 0.435 | 25.4 |
| Congestive Heart Failure (%) | 9.3 | 8.2 | 7.3 | 5.8 | 0.123 | 7.9 |
| Peripheral Vascular Disease (%) | 20.3 | 19.1 | 18.4 | 17.7 | 0.625 | 19.1 |
| Diabetes Mellitus (%) | 36.7 | 35.8 | 29.0 | 18.0 | <0.001 | 31.6 |
| History of Parathyroidectomy (%) | 4.4 | 5.4 | 6.7 | 10.3 | <0.001 | 6.2 |
| Laboratory data | ||||||
| iPTH, pg/mL (median [IQR]) | 149.6 (97.2, 185.0) | 244.0 (220.0, 271.0) | 371.0 (334.0, 419.9) | 691.8 (570.0, 889.2) | <0.001 | 265.2 (195.0, 392.0) |
| Calcium, mg/dL (mean [SD]) | 9.6 (0.9) | 9.3 (0.9) | 9.4 (0.9) | 9.7 (0.9) | <0.001 | 9.5 (0.9) |
| Phosphate, mg/dL (mean [SD]) | 5.2 (1.3) | 5.3 (1.3) | 5.7 (1.4) | 6.1 (1.5) | <0.001 | 5.5 (1.4) |
| Albumin, g/dL (mean [SD]) | 3.8 (0.4) | 3.7 (0.4) | 3.8 (0.4) | 3.8 (0.4) | 0.004 | 3.8 (0.4) |
| Kt/V (mean [SD]) | 1.4 (0.3) | 1.4 (0.3) | 1.4 (0.3) | 1.4 (0.3) | 0.090 | 1.4 (0.3) |
| Dialysate Calcium, mEq/L (mean [SD]) | 2.8 (0.2) | 2.8 (0.2) | 2.8 (0.3) | 2.8 (0.3) | 0.471 | 2.8 (0.2) |
| Vitamin D Receptor Agonist (%) | <0.001 | |||||
| Both | 0.0 | 0.2 | 0.0 | 0.2 | 0.1 | |
| Intravenous Only | 58.2 | 35.3 | 45.4 | 65.7 | 48.7 | |
| Oral Only | 29.6 | 37.1 | 27.1 | 11.9 | 28.7 | |
| Phosphate Binder (%) | <0.001 | |||||
| Both | 25.3 | 21.6 | 22.9 | 24.1 | 23.3 | |
| Non–Calcium-based Only | 12.0 | 15.0 | 20.3 | 33.6 | 18.4 | |
| Calcium-based Only | 49.8 | 46.6 | 41.6 | 29.6 | 43.6 |
BMI, body mass index; iPTH, intact parathyroid hormone; IQR, interquartile range; SD, standard deviation
aDifferences were evaluated by one-way analysis of variance or Kruskal-Wallis test for continuous variables and by chi-square test for categorical variables.