Table 1.

Characteristics of records, patients, and facilities in the 2000 USRDS dialysis population included in studya

ParameterLowest QuintileSecond QuintileThird QuintileFourth QuintileHighest QuintileP
Hematocrit (n = 1,699,056)
    range in values15.0 to 31.331.3 to 33.933.9 to 35.735.7 to 37.837.8 to 60.0
    no. of records339,812339,811339,811339,811339,811
    epo dose (units)b89,459.6 ± 74,644.271,299.8 ± 61,824.963,351.4 ± 55,356.559,784.7 ± 52,332.758,620.5 ± 51,041.9<0.0001d
    epo dose (units) per hct3197.3 ± 2780.02184.6 ± 1898.31824.4 ± 1595.81631.6 ± 1429.31459.8 ± 1275.1<0.0001
    intravenous iron (per record)c
        yes142,368 (41.9)142,980 (42.1)147183 (43.3)155,162 (45.7)168,676 (49.6)<0.0001e
        no197,444 (58.1)196,831 (57.9)192628 (56.7)184,649 (54.3)171,135 (50.4)
    URR (column%)
        <60%31,813 (9.4)21,910 (6.4)18,866 (5.6)18,437 (5.4)21,083 (6.2)<0.0001
        60 to 65%31,177 (9.2)27,338 (8.0)26,238 (7.7)26,307 (7.7)29,103 (8.6)
        65 to <70%63,548 (18.7)65,495 (19.3)66,696 (19.6)67,944 (20.0)70,567 (20.8)
        70 to <75%84,320 (24.8)96,740 (28.5)101,691 (29.9)102.478 (30.2)100,650 (29.6)
        ≥75%98,599 (29.0)108,083 (31.8)109,429 (32.2)10,145 (32.1)103,678 (30.5)
        missing30,355 (8.9)20,245 (6.0)16,891 (5.0)15,500 (4.6)14,730 (4.3)
Patients (n = 228,831)
    range in values15.0 to 32.132.1 to 33.933.9 to 35.135.1 to 36.536.5 to 58.8
    no. of patients4576745766457664576645766
    records per patient5.0 ± 3.97.7 ± 4.08.6 ± 3.88.7 ± 3.77.0 ± 4.0<0.0001
    cumulative epo dose (units)87,661.3 ± 65,672.374,600.0 ± 50,789.161,981.7 ± 42,510.555,311.8 ± 38,176.750,354.0 ± 37,856.2<0.0001
    cumulative epo dose per hct3032.3 ± 2347.72275.8 ± 1557.41809.4 ± 1245.31559.6 ± 1082.01333.5 ± 1008.8<0.0001
    gender
        male22,905 (50.1)22,763 (49.7)23,245 (50.8)24,154 (52.8)25,918 (56.6)<0.0001
        female22,862 (50.0)23,003 (50.3)22,521 (49.2)21,612 (47.2)19,848 (43.4)
    age (yr)59.1 ± 17.759.4 ± 16.759.5 ± 16.559.2 ± 16.758.4 ± 17.0<0.0001
    race
        white25,334 (55.4)25,268 (55.2)25,279 (55.2)25,247 (55.2)25,320 (55.3)<0.0001
        black17,928 (39.2)17,651 (38.6)17,426 (38.1)17,375 (38.0)17,409 (38.0)
        other2505 (5.5)2847 (6.2)3061 (6.7)3144 (6.9)3037 (6.6)
    incidence
        yes15,947 (34.8)8975 (19.6)6623 (14.5)6637 (14.5)9039 (19.8)<0.0001
        no29,820 (65.2)36,791 (80.4)39,143 (85.5)39,129 (85.5)36,727 (80.3)
    Charlson Comorbidity Index4.5 ± 3.14.0 ± 2.93.6 ± 2.73.4 ± 2.73.4 ± 2.7<0.0001
    hospital days during year25.8 ± 29.518.7 ± 24.713.8 ± 21.112.2 ± 19.412.2 ± 19.8<0.0001
    cause of ESRD
        hypertension18,359 (40.1)19,176 (41.9)18,947 (41.4)18,728 (40.9)18,528 (40.5)<0.0001
        diabetes11,657 (25.5)12,020 (26.3)12,198 (26.7)12,334 (27.0)12,289 (26.9)
        other15,751 (34.4)14,570 (31.8)14,621 (32.0)14,704 (32.1)14,949 (32.7)
    employment
        unemployed8160 (17.8)7774 (17.0)7538 (16.5)7708 (16.8)8174 (17.9)<0.0001
        employed2398 (5.2)2473 (5.4)2622 (5.7)2663 (5.8)3162 (6.9)
        retired14,457 (31.6)14,282 (31.2)14,213 (31.1)14,102 (30.8)13,772 (30.1)
        disabled8030 (17.6)7413 (16.2)7273 (15.9)7174 (15.7)7097 (15.5)
        other3086 (6.7)3177 (6.9)3376 (7.4)3264 (7.1)3159 (6.9)
        missing9636 (21.1)10,647 (23.3)10,744 (23.5)10,855 (23.7)10,403 (22.7)
    ecological factors
        health access0.16 ± 0.920.19 ± 0.920.18 ± 0.920.16 ± 0.900.17 ± 0.92<0.0001
        socioeconomic statusto 0.26 ± 1.03−0.29 ± 0.99−0.31 ± 1.00−0.25 ± 1.06−0.23 ± 1.11<0.0001
        poverty factor0.53 ± 1.270.45 ± 1.220.41 ± 1.200.39 ± 1.191.22 ± 0.41<0.0001
        urban factor2.06 ± 3.051.96 ± 2.851.97 ± 2.801.99 ± 2.752.00 ± 2.79<0.0001
    intravenous iron (during year)
        yes25,752 (56.3)31,694 (69.3)33,349 (72.9)33,987 (74.3)33,073 (72.3)<0.0001
        no20,015 (43.7)14,072 (30.8)12,417 (27.1)11,779 (25.7)12,693 (27.7)
Facilities (n = 3725)
    range in values15.3 to 33.633.6 to 34.234.2 to 34.834.8 to 35.435.4 to 43.8
    no. of facilities745745745745745
    no. of patients49.8 ± 42.265.0 ± 43.466.9 ± 43.465.9 ± 43.859.6 ± 41.2<0.0001
    no. of records347.5 ± 335.0483.8 ± 354.3506.8 ± 351.4494.6 ± 350.8447.9 ± 331.4<0.0001
    records per patient6.0 ± 2.47.1 ± 1.57.3 ± 1.57.2 ± 1.47.0 ± 1.7<0.0001
    cumulative epo dose (units)62,064.0 ± 23,405.163,967.3 ± 17,024.565,345.2 ± 17,138.165,191.9 ± 16,050.865,796.7 ± 17,400.80.03
    cumulative epo dose per hct per patient1994.1 ± 775.71972.6 ± 534.51982.2 ± 529.71944.0 ± 484.31908.6 ± 507.20.0005
    stations15.1 ± 8.516.4 ± 8.216.4 ± 8.016.9 ± 8.216.0 ± 8.0<0.0011
    patients per station4.0 ± 3.04.4 ± 2.34.8 ± 3.04.6 ± 2.54.4 ± 2.20.0001
    profit status
        profit454 (61.0)553 (74.2)620 (83.2)649 (87.1)643 (86.3)<0.001
        nonprofit and government276 (37.1)189 (25.4)119 (16.0)94 (12.6)97 (13.0)
        missing15 (2.0)3 (0.4)6 (0.8)2 (0.3)5 (0.7)
  • a epo, epoetin α; hct, hematocrit; URR, urea reduction ratio; USRDS, US Renal Data System.

  • b Continuous variables expressed as means ± SD.

  • c Categorical variables expressed as n (%).

  • d ANOVA.

  • e χ2.