Table 1.
Characteristics of the study cohort overall and by UF rate at baseline
| Patient characteristics | Overall (N = 15 414) | UF rate ≤13 mL/h/kga (n = 14 065) |
UF rate >13 mL/h/kga (n = 1312) |
|---|---|---|---|
| Demographics | |||
| Age (years), mean ± SD | 76.3 ± 6.3 | 76.3 ± 6.3 | 76.4 ± 6.3 |
| Female, n (%) | 7838 (50.8) | 7054 (50.2) | 763 (58.2) |
| Race, n (%) | |||
| White | 10 626 (68.9) | 9715 (69.1) | 881 (67.1) |
| Black | 4063 (26.4) | 3745 (26.6) | 312 (23.8) |
| Asian | 477 (3.1) | 382 (2.7) | 94 (7.2) |
| Native American | 91 (0.6) | 80 (0.6) | 11 (0.8) |
| Other/unknown | 157 (1.0) | 143 (1.0) | 14 (1.1) |
| Hispanic ethnicity, n (%) | 1237 (8.0) | 1097 (7.8) | 136 (10.4) |
| Missing | 48 (0.3) | 46 (0.3) | 2 (0.2) |
| Dual Medicare/Medicaid eligible, n (%) | 4151 (26.9) | 3718 (26.4) | 421 (32.1) |
| Catheter vascular access, n (%) | 9732 (63.1) | 8900 (63.3) | 808 (61.6) |
| Missing | 37 (0.2) | 57 (0.4) | 3 (0.3) |
| Census data | |||
| Unemployed, median (IQR) | 9.3 (6.8–12.4) | 9.3 (6.8–12.4) | 9.5 (7.0–12.7) |
| Missing, n (%) | 140 (0.9) | 129 (0.9) | 11 (0.8) |
| Below poverty line, median (IQR) | 13.9 (8.3–20.9) | 13.8 (8.2–20.8) | 15.0 (8.7–22.0) |
| Missing, n (%) | 141 (0.9) | 130 (0.9) | 11 (0.8) |
| Less than a high school education, median (IQR) | 14.0 (8.8–21.1) | 13.9 (8.8–21.0) | 15.1 (9.2–22.4) |
| Missing, n (%) | 140 (0.9) | 129 (0.9) | 11 (0.8) |
| Monthly rent (US$), median (IQR) | 859 (686–1069) | 857 (685–1065) | 874 (692–1105) |
| Missing, n (%) | 312 (2.0) | 282 (2.0) | 30 (2.3) |
| Annual household income (US$), median (IQR) | 48 125 (38 245–63 555) | 48 151 (38 397–63 653) | 47 639 (37 132–63 010) |
| Missing, n (%) | 144 (0.9) | 132 (0.9) | 12 (0.9) |
| Hospital days in the 30 days prior to UF rate ascertainment, mean ± SD | 0.9 ± 3.0 | 0.9 ± 2.9 | 1.2 ± 3.5 |
| Comorbid medical conditions, n (%) | |||
| Coronary artery disease | 8547 (55.4) | 7781 (55.3) | 747 (56.9) |
| Myocardial infarction | 2110 (13.7) | 1886 (13.4) | 216 (16.5) |
| Unstable angina | 2598 (16.9) | 2351 (16.7) | 239 (18.2) |
| Heart failure | 9540 (61.9) | 8575 (61.0) | 942 (71.8) |
| Coronary revascularization | 3337 (21.6) | 3058 (21.7) | 271 (20.7) |
| ICD or pacemaker | 950 (6.2) | 869 (6.2) | 80 (6.1) |
| Ventricular fibrillation or another arrhythmia | 2405 (15.6) | 2153 (15.3) | 245 (18.7) |
| Valvular heart disease | 4580 (29.7) | 4067 (28.9) | 498 (38.0) |
| Stroke or TIA | 2873 (18.6) | 2613 (18.6) | 243 (18.5) |
| Hypertension | 15276 (99.1) | 13 938 (99.1) | 1301 (99.2) |
| Peripheral artery disease | 5685 (36.9) | 5141 (36.6) | 525 (40.0) |
| Diabetes mellitus | 10 523 (68.3) | 9613 (68.3) | 884 (67.4) |
| Hyperlipidemia | 11 468 (74.4) | 10 512 (74.7) | 930 (70.9) |
| Liver disease | 1136 (7.4) | 996 (7.1) | 136 (10.4) |
| Chronic lung disease | 5889 (38.2) | 5317 (37.8) | 554 (42.2) |
| Depression | 2392 (15.5) | 2148 (15.3) | 234 (17.8) |
| Biometric measurements | |||
| eGFR at HD initiation (mL/min/1.73 m2), mean ± SD | 10.4 ± 4.4 | 10.4 ± 4.3 | 10.6 ± 4.5 |
| Missing, n (%) | 162 (1.1%) | 147 (1.0%) | 14 (1.1%) |
| HD treatments in the 30-day UF rate ascertainment period, mean ± SD | 12.3 ± 1.6 | 12.3 ± 1.6 | 12.2 ± 1.7 |
| Delivered UF rate (mL/h/kg)a, mean ± SD | 7.7 ± 4.0 | 7.0 ± 3.2 | 15.6 ± 2.8 |
| Predialysis systolic BP (mmHg), mean ± SD | 147.3 ± 19.7 | 147.1 ± 19.6 | 148.7 ± 20.0 |
| Missing, n (%) | 170 (1.1) | 142 (1.0) | 20 (1.5) |
| Delivered treatment time (min), mean ± SD | 208.7 ± 24.5 | 209.8 ± 24.3 | 196.5 ± 23.4 |
| UF volume (L), mean ± SD | 1.9 ± 1.0 | 1.8 ± 0.9 | 3.0 ± 0.7 |
| Postdialysis weight (kg), mean ± SD | 73.3 ± 17.9 | 74.5 ± 17.9 | 60.2 ± 12.3 |
| Interdialytic weight gain (kg), mean ± SD | 2.0 ± 1.2 | 1.9 ± 1.2 | 3.1 ± 1.1 |
| Prescribed ‘dry’ weight (kg), mean ± SD | 73.3 ± 18.0 | 74.6 ± 17.9 | 59.7 ± 12.2 |
| Body mass index (kg/m2), mean ± SD | 27.7 ± 7.0 | 28.1 ± 7.0 | 24.0 ± 5.3 |
| Predialysis diastolic BP (mmHg), mean ± SD | 72.3 ± 10.1 | 72.3 ± 10.0 | 72.5 ± 10.6 |
| Missing, n (%) | 170 (1.1) | 142 (1.0) | 20 (1.5) |
| Serum albumin (g/L), mean ± SD | 3.6 ± 0.5 | 3.6 ± 0.4 | 3.6 ± 0.5 |
| Missing, n (%) | 161 (1.0) | 141 (1.0) | 18 (1.4) |
| Serum potassium (mEq/L), mean ± SD | 4.5 ± 0.6 | 4.4 ± 0.6 | 4.6 ± 0.7 |
| Missing, n (%) | 169 (1.1) | 148 (1.1) | 18 (1.4) |
| Calcium (mg/L), mean ± SD | 8.9 ± 0.7 | 9.0 ± 0.7 | 8.8 ± 0.7 |
| Missing, n (%) | 149 (1.0%) | 130 (0.9%) | 17 (1.3%) |
a
Thirty-seven patients who were missing delivered UF rate (due to missing treatment time, UF volume or postdialysis weight) at baseline were excluded.
TIA, transient ischemic attack.