Table 1. Distributions of selected patient characteristics

Distribution across Full CohortStratum-Specific Distribution by Baseline Iron Dose (%)
n(%)None> 0 to 1000 mg> 1000 mgP-value
The two 6-mo enrollment periods were January 1, 1996 to June 30, 1996 and July 1, 1996 to December 31, 1996.
a The baseline iron exposure period was designated as the 6 mo immediately following the enrollment period.
b Demographic and comorbidity variables were collected at the end of the enrollment period.
c Mean values during the enrollment period.
Baseline period iron dosinga total iron dose received (mg)
        none7241(26.5)----
        > 0 to 7003327(12.2)---
        > 700 to 10003569(13.1)---
        > 1000 to 18006391(23.4)---
        > 18006752(24.8)---
Demographic and comorbidity variables
    gender
        male13744(50.4)27.624.647.80.0026
        female13536(49.6)25.526.048.6
    age (yr)b
        18 to <403097(11.4)28.025.546.50.0021
        40 to <609193(33.7)27.624.348.2
        ≥ 6014990(55.0)25.625.948.5
    race
        Asian/Pacific Islander433(1.6)46.222.931.0< 0.0001
        Black12543(46.0)24.925.249.9
        Native American218(0.8)22.937.639.5
        White12928(47.4)26.825.048.2
        other1158(4.2)35.026.938.1
    diabetesb
        no15077(55.3)28.725.345.9< 0.0001
        yes12203(44.7)23.825.251.0
    duration of ESRD (yr)b
        0.5 to < 211390(41.8)22.723.753.5< 0.0001
        2 to < 47386(27.1)27.225.847.1
        ≥48504(31.2)31.126.941.9
Enrollment period variablesc hospitalizations
        015008(55.0)30.525.244.3< 0.0001
        ≥ 112272(45.0)21.725.453.0
    IV antibiotic doses administered
        019504(71.5)27.825.147.0< 0.0001
        12056(7.5)24.526.848.8
        ≥ 25720(21.0)22.925.351.8
    epoetin (units/mo)
        none1838(6.7)64.513.122.4< 0.0001
        > 0 to 20,0003209(11.8)29.530.540.0
        20,000 to 40,0006925(25.4)25.828.545.7
        > 40,00015308(56.1)21.724.254.1
    albumin (g/dl)
        < 3.52727(10.0)24.323.452.4< 0.0001
        3.5–413525(49.6)25.225.049.7
        > 411028(40.4)28.726.145.2
    AST/SGOT (U/L)
        < 5026651(97.7)26.325.348.3< 0.0001
        ≥ 50629(2.3)35.323.141.7
    bicarbonate (mEq/L)
        < 184634(17.0)25.724.050.30.0004
        18 to < 2111121(40.8)26.225.348.5
        ≥ 2111525(42.3)27.225.847.0
    calcium (mg/dl)
        < 82131(7.8)25.623.950.5< 0.0001
        8 to < 911510(42.2)25.425.149.6
        9 to < 1010950(40.1)27.026.346.8
        10 to < 112576(9.4)30.623.346.1
        ≥ 11113(0.4)31.020.448.7
    ferritin (ng/ml)
        < 1005636(20.7)35.423.441.2< 0.0001
        100 to < 80018991(69.6)22.825.751.6
        ≥ 8002653(9.7)34.826.438.8
    hemoglobin (g/dl)
        < 8574(2.1)32.216.251.6< 0.0001
        8 to < 1010128(37.1)23.223.353.4
        10 to < 1215549(57.0)27.626.845.6
        ≥ 121029(3.8)40.326.333.3
    phosphate (mg/dl)
        < 57022(25.7)28.426.045.6< 0.0001
        5 to < 713877(50.9)26.925.447.8
        ≥ 76381(23.4)23.824.351.9
    PTH (pg/ml)
        < 20014773(57.4)26.625.148.30.014
        200 to < 5006286(24.4)25.924.849.3
        500 to < 10002637(10.3)26.525.348.2
        ≥ 10002039(7.9)30.225.244.6
    TSAT (%)
        < 206197(22.7)26.623.050.5< 0.0001
        20 to < 3516522(60.6)24.825.150.1
        35 to < 503799(13.9)30.529.440.1
        ≥ 50762(2.8)44.826.329.0
    URR (%)
        < 624213(15.4)24.323.252.5< 0.0001
        ≥ 6223067(84.6)27.025.747.4