Table 2.

Characteristics of all patients.

VariableHb RangeGroup Effect P ValueTime Effect
<8.5 g/dl (n=249)8.5–9.99 g/dl (n=697)10.0–11.49 g/dl (n=1272)11.5–12.99 g/dl (n=1067)13–14.49 g/dl (n=359)>14.5 g/dl (n=87)Unit ChangeEstimated P Value
Age (yr)9.9±5.49.2±4.99.8±4.610.1±4.410.1±5.110.6±5.40.18
Pubertal male (%)11.210.316.419.218.719.50.020.1140.19
PD vintage (yr)1.7±1.61.8±1.61.7.±1.31.7±1.31.6±1.51.3±1.70.03
Use of biocompatible PD fluids (%)22.126.831.835.330.935.60.42−0.1200.11
PET 4h-D/Pcreatinine0.68±0.16 (n=61)0.68±0.14 (n=158)0.66±0.12 (n=247)0.64±0.13 (n=244)0.61±0.16 (n=70)0.63±0.13 (n=22)0.59−0.00320.55
Estimated deviation from dry weight (%)2.02±3.712.09±2.901.41±2.461.32±2.041.49±3.291.51±2.35<0.001−0.05020.43
PD fluid turnover (L/m2 per day)6.33±2.756.65±2.556.98±2.606.76±2.536.85±2.916.44±2.630.070.587<0.001
Ultrafiltration volume (L/m2 per day)0.65±0.410.56±0.350.55±0.370.50±0.320.57±0.410.53±0.450.0080.0353<0.001
Urine volume (L/m2 per day)0.40±0.520.55±0.570.61±0.530.71±0.590.67±0.660.73±0.680.003−0.088<0.001
Total fluid output (L/m2 per day)1.07±0.55 (n=225)1.13±0.55 (n=599)1.18±0.54 (n=1097)1.23±0.53 (n=939)1.26±0.64 (n=300)1.27±0.68 (n=68)0.200.0423<0.001
ESA use (%)
 None4.84.23.97.716.431.0<0.001−0.2120.03
 Epoetin79.580.277.373.571.957.50.003−0.1540.02
 Darbepoetin14.914.617.317.210.611.50.210.2250.004
ESA dose (1000 U/m2 per week)7.12±4.53 (n=191)6.12±3.22 (n=545)5.26±3.12 (n=1002)4.89±3.25 (n=769)4.19±3.13 (n=240)5.83±4.81 (n=52)<0.0010.00360.96
Iron use (%)
 None18.120.117.417.215.323.00.440.288<0.001
 Oral60.667.065.368.666.370.10.20−0.361<0.001
 Intravenous (with or without oral)21.312.917.314.218.46.90.070.08080.29
Biochemistry
 Hemoglobin (g/dl)7.6±0.69.3±0.310.7±0.312.1±0.313.5±0.415.2±0.70.020.0223<0.001
 Serum ferritin (ng/ml)262 (125–486) (n=130)234 (121–402) (n=429)188 (85–356) (n=768)160 (75–312) (n=625)164 (66–336) (n=211)128 (59–304) (n=56)0.0415.3<0.001
 Serum albumin (g/l)33.1±6.635.4±5.136.3±4.937.2±4.738.6±4.939.1±4.9<0.0010.08840.34
 Plasma PTH (pg/ml)452 (177–740)325 (122–675)218 (99–494)213 (104–436)215 (95–465)197 (79–412)<0.00115.60.06
Cardiovascular variables
 Systolic BP SDS1.34±1.631.12±1.390.92±1.200.87±1.130.72±1.360.66±1.56<0.001−0.109<0.001
 Diastolic BP SDS1.19±1.271.03±1.250.90±1.070.85±1.030.74±1.230.74±1.440.002−0.153<0.001
 Hypertensive (%)49.843.536.936.432.142.70.002−0.1460.005
 LV mass index66.8±49.4 (n=80)48.9±22.5 (n=263)48.4±27.5 (n=489)48.6±33.1 (n=414)44.2±26.1 (n=134)53.1±30.2 (n=32)<0.001−2.450.01
 LV hypertrophy (%)62.543.041.539.437.343.80.05−0.1350.08
  • Data are given as mean ± SD, median (IQR), or percentage as appropriate. Group effect column denotes differences between Hb group means. Time effect column shows the unit change per observation year. Numbers in parentheses denote available observations. PET 4h-D/Pcreatinine, peritoneal equilibration test 4 hour dialysate plasma to creatinine ratio; SDS, standard deviation score; LV, left ventricular.