Table 1.

Baseline characteristics, by CKD and hemoglobin quintilesa

Baseline CharacteristicsCKDb (GFR <60 ml/min per 1.73 m2; Range 11.9 to 59.97)No CKDb (GFR ≥60 ml/min per 1.73 m2; Range 60.0 to 129.8)
Lowest Hemoglobin Quintile (n = 352; mean 13.1 g/dl)cOther Hemoglobin Quintiles (n = 1287; mean 15.2 g/dl)cP ValueLowest Hemoglobin Quintile (n = 258; mean 13.4 g/dl)cOther Hemoglobin Quintiles (n = 1177; mean 15.3 g/dl)cP Value
Age (yr; mean [SE])73.9 (0.46)70.8 (0.22)0.000159.6 (0.42)59.4 (0.18)0.63
Mean arterial BP (mmHg; mean [SE])105.2 (0.74)105.1 (0.35)0.93101.4 (0.69)103.6 (0.34)0.005
Total serum cholesterol (mmol/L; mean [SE])5.9 (0.06)6.1 (0.03)0.00025.8 (0.06)6.0 (0.03)0.0002
Fibrinogen (mg/dl; mean [SE])4.6 (0.07)4.1 (0.03)<0.00014.0 (0.06)3.9 (0.04)0.027
Body mass index (kg/m2; mean [SE])25.0 (0.21)25.0 (0.11)0.7726.5 (0.27)27.7 (0.13)0.0002
Mean hemoglobin (g/dl; mean [SE])13.1 (0.05)15.2 (0.03)<0.000113.5 (0.05)15.3 (0.03)<0.0001
Mean GFR (ml/min per 1.73 m2; mean [SE])44.7 (0.56)49.2 (0.23)<0.000170.3 (0.60)70.2 (0.24)0.85
Mean alcohol consumption, standard drinks per week (mean [SE])4.3 (0.52)5.8 (0.27)0.017.7 (0.91)8.1 (0.41)0.72
Male (n [%])131 (37.2)519 (40.3)0.29115 (44.6)563 (47.8)0.34
Severe hypertensiond (n [%])200 (56.8)675 (52.5)0.1582 (31.8)441 (37.5)0.09
Diabetes (n [%])25 (7.1)114 (8.9)0.2917 (6.6)91 (7.7)0.53
Anemia (n [%])50 (14.2)0<0.000117 (6.6)0<0.0001
Pre-existing CHD (n [%])67 (19.0)258 (20.1)0.6720 (7.8)130 (11.1)0.12
Current smoker (n [%])23 (6.5)181 (14.1)0.000124 (9.3)221 (18.8)0.0002
  • a CKD, chronic kidney disease; CHD, coronary heart disease.

  • b CKD is defined according to National Kidney Foundation criteria of GFR <60 ml/min per 1.73 m2, with GFR estimated using the Cockcroft-Gault equation.

  • c Mean hemoglobin for men and women combined. For women, hemoglobin in the lowest quintile ranged from 8.4 to 13.5 g/dl, whereas hemoglobin in other quintiles ranged from 13.6 to 22.4 g/dl. For men, hemoglobin in the lowest quintile ranged from 7.6 to 14.6 g/dl, whereas hemoglobin in other quintiles ranged from 14.7 to 19.3 g/dl.

  • d Severe hypertension is defined according to World Health Organization/International Society of Hypertension category grade 2 or 3, i.e., a previous diagnosis of hypertension and current use of antihypertensive medication, or systolic BP ≥ 160 mmHg, or diastolic BP ≥ 100 mmHg at baseline examination.