Table 1

Baseline characteristics of participants enrolled in the study (n=5515) with stratification by haemoglobin concentration

VariableTotalHaemoglobin concentration, g/dLP value
Valuen<9.0
(n=1096)
9.0 to 9.9
(n=1362)
10.0 to 10.9
(n=1608)
11.0 to 11.9
(n=1009)
12.0 to 12.9
(n=335)
≥13.0
(n=105)
Demographics
 Age, yr64 (55 to 72)551566 (57 to 74)65 (57 to 73)63 (55 to 72)62 (54 to 71)62 (53 to 69)58 (50 to 71)<0.001
 Sex, female, %37.8551543.240.037.633.029.327.6<0.001
 Duration of dialysis, yr2.9 (0.5 to 8.0)55150.7 (0.03 to 4.9)3.3 (0.6 to 8.2)3.5 (0.8 to 8.9)3.7 (0.8 to 9.1)3.4 (0.7 to 9.0)2.0 (0.6 to 2.7)<0.001
 Past smoker, %19.5441418.819.219.819.919.721.40.69
 Current smoker, %19.319.318.419.119.122.427.4
 Married, %71.0537572.472.071.069.967.967.00.48
 Living alone, %11.6539311.610.412.211.014.614.60.44
 Employed, %70.7493276.273.070.166.262.864.5<0.001
Cause of end-stage kidney disease, %
 Hypertension5.148335.25.15.64.34.54.40.09
 Glomerulonephritis44.441.145.746.245.042.830.8
 Diabetic nephropathy34.938.233.933.434.536.038.5
 Other disease15.615.515.314.816.216.826.4
Comorbid conditions, %
 Hypertension71.5548373.272.072.769.966.859.60.002
 Diabetes mellitus36.3549938.836.234.736.335.539.10.37
 Cardiovascular disease35.7551340.835.534.230.938.243.8<0.001
 Lung disease2.155071.92.31.62.82.12.90.39
 Liver disease11.1551211.810.211.611.011.99.50.76
 Gastrointestinal bleeding12.6549614.413.012.210.712.613.50.22
 Cancer8.154758.28.77.87.97.56.70.94
 Peripheral vascular disease13.7551313.513.013.814.514.312.40.93
 Psychiatric disorder2.055111.91.82.11.92.13.80.79
 Neurological disease11.7551213.411.810.611.111.615.20.26
 Joint and bone disease12.055129.211.212.614.413.713.30.007
Dialysis
 BMI, kg/m2 20.7 (18.9 to 22.9)526820.7 (18.7 to 22.8)20.6 (18.5 to 22.7)20.9 (19.0 to 22.9)20.6 (18.9 to 22.8)21.2 (19.3 to 23.3)21.7 (18.8 to 24.1)<0.001
 Systolic BP, mm Hg150 (135 to 166)5365151 (132 to 167)151 (138 to 167)150 (136 to 167)150 (134 to 165)150 (130 to 162)150 (130 to 161)0.09
 Diastolic BP, mm Hg78 (70 to 87)535974 (66 to 84)78 (70 to 87)79 (70 to 86)80 (70 to 88)80 (70 to 88)82 (70 to 92)<0.001
 Kt/V, single pool1.28 (1.09 to 1.48)44151.20 (0.94 to 1.44)1.29 (1.11 to 1.50)1.30 (1.11 to 1.50)1.30 (1.10 to 1.49)1.26 (1.07 to 1.42)1.31 (1.05 to 1.47)<0.001
 nPCR, g/kg/day0.97 (0.83 to 1.12)43530.91 (0.76 to 1.08)0.98 (0.84 to 1.12)0.99 (0.83 to 1.14)1.00 (0.84 to 1.14)0.98 (0.84 to 1.14)0.97 (0.87 to 1.13)<0.001
 Residual KF, %‡33.8528645.431.930.829.430.730.2<0.001
Laboratory data
 Serum albumin, g/dl3.8 (3.5 to 4.0)51673.5 (3.2 to 3.8)3.7 (3.5 to 4.0)3.8 (3.6 to 4.0)3.9 (3.6 to 4.1)3.9 (3.6 to 4.1)3.8 (3.4 to 4.1)<0.001
 Ferritin, ng/ml174 (72 to 410)3568237 (107 to 626)175 (74 to 406)168 (69 to 392)151 (65 to 354)134 (52 to 297)88 (39 to 166)<0.001
 TSAT, %23.6 (16.6 to 32.3)237021.3 (14.3 to 31.2)22.2 (18.5 to 22.7)24.2 (17.6 to 32.6)25.2 (18.3 to 33.1)28.4 (20.0 to 35.4)22.9 (17.4 to 29.9)<0.001
 Calcium, mg/dl 9.2 (8.7 to 9.8)50619.0 (8.5 to 9.6)9.2 (8.7 to 9.8)9.2 (8.7 to 9.8)9.2 (8.7 to 9.8)9.3 (8.8 to 10.0)9.4 (8.9 to 10.0)<0.001
 Phosphorus, mg/dl5.4 (4.5 to 6.4)54635.1 (4.2 to 6.1)5.3 (4.4 to 6.3)5.4 (4.6 to 6.4)5.5 (4.6 to 6.6)5.6 (4.7 to 6.6)5.7 (4.8 to 6.8)<0.001
 Intact PTH, pg/ml142 (66 to 253)3950160 (72 to 280)142 (63 to 251)141 (69 to 241)130 (63 to 245)140 (63 to 243)141 (69 to 270)0.08
Prescription of drugs
 Calcium channel blocker, %54.5528060.257.653.050.549.237.0<0.001
 Beta blocker, %15.1528014.914.514.916.416.112.00.73
 Diuretic, %30.4528036.329.528.130.730.018.0<0.001
 Statin, %10.5528010.19.911.110.311.811.00.86
 ARB, %36.1528035.838.336.836.228.525.00.006
 ACEI, %10.6528011.510.99.811.29.37.00.50
 Antiplatelet drug, %37.3528037.136.838.634.737.847.00.15
 Anticoagulant drug, %4.052804.63.63.84.13.16.00.60
 Benzodiazepine, %17.2528016.816.717.216.420.425.00.19
 Intravenous iron use, %30.0543927.129.131.531.530.434.00.14
 ESA use, %82.6502986.388.784.179.062.453.0<0.001
 ESA dose, unit/week4500 (1500 to 6750)50296000 (3000 to 9000)4500 (2438 to 9000)4000 (1500 to 6000)3000 (1313 to 6000)2000 (0 to 4500)0 (0 to 3000)<0.001
  • For continuous variables, median and IQR are shown.

  • *Albumin-corrected value; calcium + (4.0-albumin) if albumin is less than 4.0 g/dL.

  • †Urine volume ≥200 mL/day or daily urine collection volume of ≥1 cup.

  • ACEI, angiotensin-converting-enzyme inhibitor; ARB, angiotensin II type one receptor blocker;BMI, body mass index; BP, blood pressure; ESA, erythropoietin-stimulating agents; KF, kidney function; nPCR, normalised protein catabolic rate; PTH, parathyroid hormone;TSAT, transferrin saturation; yr, year.