Table 1.

Baseline characteristics in subgroups divided by quartiles of total iron saturationa

VariableISAT (%)P for linear trend
<12 (n = 118)12 to 17 (n = 114)17.1 to 23 (n = 109)>23 (n = 112)
Age (yr)70.9 ± 9.066.4 ± 10.269.9 ± 9.468.3 ± 10.80.29
Race (% black)28 (24)25 (22)30 (27)34 (30)0.16
DM60 (51)74 (65)62 (57)75 (67)0.047
CVD84 (71)75 (66)65 (60)64 (57)0.017
Charlson index3.1 ± 1.92.8 ± 1.92.5 ± 1.82.6 ± 1.50.029
SBP (mmHg)153 ± 27150 ± 27157 ± 31153 ± 160.5
DBP (mmHg)72 ± 1574 ± 1573 ± 1676 ± 160.076
Estimated GFR (ml/min/1.73m2)32.1 ± 14.631.7 ± 12.533.0 ± 11.935.1 ± 15.20.068
K/DOQI stage (% 2/3/4/5)7/44/41/83/51/38/83/54/40/35/60/28/70.07
Hemoglobin (g/dl)11.3 ± 1.711.9 ± 1.511.7 ± 1.512.0 ± 1.60.001
Serum albumin (g/dl)3.5 ± 0.53.5 ± 0.53.6 ± 0.43.6 ± 0.60.18
WBC (1000/mm3)7.7 ± 2.57.4 ± 2.47.3 ± 2.27.1 ± 2.30.04
Serum ferritin (ng/ml)85 (67 to 106)108 (91 to 128)133 (114 to 156)167 (140 to 199)<0.001
Serum iron (mcg/dl)28 ± 1049 ± 1062 ± 1494 ± 35<0.001
TIBC (mcg/dl)341 ± 88335 ± 63315 ± 65293 ± 74<0.001
Proteinuria (g/24 h)833 (625 to 1110)886 (659 to 1192)841 (635 to 1115)1119 (825 to 1519)0.2
ASA use75 (64)72 (63)65 (60)64 (57)0.26
ACEI/ARB use80 (68)92 (81)86 (79)91 (81)0.027
Statin use60 (51)76 (67)68 (62)72 (64)0.07
Calcitriol use36 (30)43 (38)44 (40)38 (34)0.5
  • a Data are presented as means ± SD, number (%), or geometric means ± 95% confidence intervals. Comparisons were made by χ2 test for trend.

  • DM, diabetes mellitus; CVD, cardiovascular disease; SBP, systolic blood pressure; DBP, diastolic blood pressure; K/DOQI, Kidney Disease Outcomes Quality Initiative; WBC, white blood cell count; TIBC, total iron binding capacity; ASA, aspirin; ACEI/ARB, angiotensin converting enzyme inhibitor/angiotensin receptor blocker.