Table 1.

Patient characteristics at baseline by exposure group (n=776,203)

CharacteristicHigh (24.0%)Low (37.8%)Bolus (12.6%)Maintenance (49.2%)Nonuser (38.2%)
Mean (SD) age (yr)60.8 (15.0)61.5 (15.0)60.6 (15.1)61.4 (14.9)61.4 (14.9)
Women (%)45.445.446.145.346.3
Race (%)
 White49.249.147.549.647.9
 Black45.844.547.844.345.0
Medicaid (%)50.951.051.950.751.6
Region (%)
 Midwest18.016.817.417.216.2
 Northeast12.312.711.912.712.3
 South51.947.155.347.350.4
 West17.222.914.922.220.7
Reported cause of ESRD (%)
 Diabetes46.444.745.845.343.3
 GN12.012.612.012.513.1
 Hypertension30.431.130.830.931.3
Mean (SD) vintage (yr)4.0 (4.1)4.3 (4.4)4.0 (4.1)4.3 (4.3)4.8 (4.6)
Mean (SD) BMI (kg/m2)27.4 (7.1)27.3 (6.8)27.1 (7.0)27.4 (6.9)26.6 (6.6)
Central venous hemodialysis catheter (%)23.821.825.521.820.4
Blood transfusion (%)8.54.910.35.36.2
Hospitalized days last month mean (SD)0.8 (2.1)0.5 (1.7)1.0 (2.3)0.5 (1.7)0.5 (1.8)
Infection last month (%)14.210.616.210.910.6
Pneumonia (%)11.98.813.29.29.5
Sepsis (%)12.38.414.18.88.8
Vascular access (%)13.49.715.010.18.9
Diabetes (%)56.652.157.153.050.9
Ischemic stroke (%)12.110.013.110.210.3
MI (%)4.22.94.63.13.1
COPD and asthma (%)20.816.522.217.216.0
Cancer (%)9.28.19.88.28.4
GI bleeding (%)6.43.97.74.23.9
Laboratory values and medications median (interquartile range)
 Index TSAT (%)23.0 (18.0–29.0)28.0 (23.0–36.0)20.0 (16.0–26.0)28.0 (22.0–35.0)31.0 (24.0–41.0)
 Ferritin (mcg/L)457 (280–641)514 (351–678)433 (240–642)505 (344–669)743 (473–977)
 Hemoglobin (g/dl)12.1 (11.3–13.0)12.2 (11.5–13.0)11.9 (11.0–12.8)12.3 (11.5–13.0)12.2 (11.4–13.0)
 Albumin (g/dl)3.90 (3.60–4.10)3.90 (3.70–4.10)3.80 (3.50–4.10)3.90 (3.70–4.10)3.90 (3.70–4.10)
 Baseline EPO (1000 u/mo)81.1 (41.5–148)52.1 (26.0–99.5)93.6 (48.4–172)56.1 (27.5–105)44.0 (19.8–88.0)
 EPO during exposure (1000 u/mo)75.0 (36.3–142)50.7 (24.2–97.5)89.1 (44.0–167)53.0 (26.0–101)47.5 (22.0–94.6)
 Iron during baseline period (mg)300 (100–500)125 (100–250)225 (0–550)200 (100–250)0 (0–50.0)
 Iron during exposure period (mg)400 (300–700)125 (100–200)700 (400–1000)200 (100–250)0 (0–0)
  • COPD, chronic obstructive pulmonary disease; u/mo, units/month.