Table 1.
Baseline Patient characteristics of 107,817 maintenance hemodialysis patients according to 5 incremental age categories
| Age Range (years) | All | 15-<45 | 45-<65 | 65-<70 | 70-<75 | ≥75 | P-for trend |
|---|---|---|---|---|---|---|---|
| N (%) | 107,817 | 19,182 (18) | 41,770 (39) | 12,562 (12) | 12,240 (11) | 22,063 (20) | N/A |
| Age (years) (mean±SD) | 60±16 | 34.6± 7.3 | 55.4± 5.6 | 67± 1.4 | 72±1.4 | 80.4±4.3 | <0.001 |
| Gender (%female) | 45 | 40 | 44 | 49 | 49 | 47 | <0.001 |
| Race (%) | |||||||
| White | 46 | 29 | 38 | 48 | 56 | 67 | <0.001 |
| Black | 35 | 49 | 40 | 31 | 26 | 20 | <0.001 |
| Hispanic | 16 | 19 | 19 | 17 | 14 | 10 | <0.001 |
| Asian | 3 | 3 | 3 | 4 | 4 | 3 | 0.01 |
| DM (%) | 58 | 33 | 66 | 71 | 65 | 51 | <0.001 |
| Vintage (time on dialysis; %) | |||||||
| <6 mo | 58 | 46 | 56 | 59 | 61 | 70 | <0.001 |
| 6-24 mo | 17 | 15 | 17 | 17 | 18 | 17 | 0.002 |
| 2-5 yr | 16 | 18 | 18 | 17 | 16 | 11 | <0.001 |
| ≥ 5 yr | 9 | 21 | 9 | 7 | 5 | 2 | <0.001 |
| Primary insurance (%) | |||||||
| Medicare | 68 | 60 | 58 | 78 | 79 | 82 | <0.001 |
| Medicaid | 6 | 12 | 9 | 2 | 2 | 1 | <0.001 |
| Other | 26 | 28 | 33 | 20 | 19 | 17 | <0.001 |
| Marital status (%) | |||||||
| Married | 47 | 33 | 49 | 54 | 54 | 47 | <0.001 |
| Divorced | 9 | 7 | 12 | 8 | 7 | 4 | <0.001 |
| Single | 28 | 59 | 31 | 18 | 13 | 11 | <0.001 |
| Widowed | 16 | 1 | 8 | 20 | 26 | 38 | <0.001 |
| Kt/V (single pool; mean±SD) | 1.52±0.35 | 1.47±0.35 | 1.49±0.35 | 1.55±0.35 | 1.56±0.36 | 1.58±0.35 | <0.001 |
| BMI (kg/m2; mean±SD) | 26.7±6.7 | 26.8±7.4 | 28±7.2 | 26.8±6.2 | 26±5.8 | 24.3±4.9 | <0.001 |
| nPNA (g/kg/day; mean±SD) | 0.95±0.25 | 0.97±0.26 | 0.96±0.26 | 0.95±0.25 | 0.93±0.25 | 0.91±0.24 | <0.001 |
| Vascular access (%) | |||||||
| AVF | 25.7 | 33.5 | 26.1 | 23.3 | 23.3 | 20.8 | <0.001 |
| AVG | 29.5 | 26.2 | 30.6 | 33.4 | 31.8 | 26.9 | 0.88 |
| Catheter | 44.5 | 40 | 43 | 42.9 | 44.5 | 52 | <0.001 |
| Other/Missing | 0.3 | 0.3 | 0.3 | 0.4 | 0.4 | 0.3 | 0.54 |
| Comorbid conditions (%) | |||||||
| Atherosclerotic heart disease | 22 | 4.4 | 18 | 28 | 31 | 33 | <0.001 |
| Cancer | 4.7 | 1 | 3.1 | 6 | 7 | 9 | <0.001 |
| Congestive heart failure | 28 | 12 | 26 | 34 | 35 | 38 | <0.001 |
| COPD | 6 | 1.1 | 5 | 8 | 9 | 9 | <0.001 |
| Cerebrovascular disease | 8 | 2.4 | 7 | 10 | 10 | 10 | <0.001 |
| Hypertension | 80 | 75 | 81 | 81 | 81 | 80 | <0.001 |
| Other cardiac diseases | 6 | 2.1 | 4.1 | 7 | 8 | 10 | <0.001 |
| Peripheral vascular disease | 12 | 3.4 | 10 | 15 | 16 | 16 | <0.001 |
| Non-Ambulatory states | 3.19 | 1.23 | 2.92 | 3.68 | 3.81 | 4.59 | <0.001 |
| Active smoking | 5 | 7 | 7 | 4.3 | 3.7 | 1.8 | <0.001 |
| Serum Levels (baseline) | |||||||
| Albumin (g/dL) | 3.67±0.5 | 3.82±0.5 | 3.68±0.5 | 3.65±0.4 | 3.62±0.4 | 3.57±0.4 | <0.001 |
| Creatinine (mg/dL) | 8.01±3.3 | 10.72±3.8 | 8.31±3.1 | 7.2±2.6 | 6.83±2.5 | 6.14±2.2 | <0.001 |
| TIBC (mg/dL) | 209±46 | 209±45 | 213±47 | 208±46 | 207±46 | 204±46 | <0.001 |
| Ferritin (ng/mL) | 380(181, 708) | 358(163, 688) | 387(185, 719) | 403(192, 723) | 393(190, 731) | 367(177, 680) | 0.065 |
| Bicarbonate (mg/dL) | 22.44±3.1 | 21.79±3.1 | 22.24±3 | 22.6±3 | 22.8±2.9 | 23.12±3 | <0.001 |
| Calcium (mg/dL) | 9.45±0.7 | 9.35±0.8 | 9.44±0.7 | 9.48±0.7 | 9.5±0.6 | 9.52±0.6 | <0.001 |
| Phosphorus (mg/dL) | 5.56±1.5 | 6.28±1.7 | 5.71±1.5 | 5.33±1.3 | 5.18±1.3 | 4.96±1.2 | <0.001 |
| Intact PTH (pg/mL) | 248(145, 422) | 341(185, 644) | 265(157, 442) | 228(134, 367) | 213(127, 341) | 200(121, 311) | <0.001 |
| Hemoglobin (g/dL) | 12.02±1.4 | 11.89±1.5 | 12.01±1.4 | 12.04±1.3 | 12.05±1.3 | 12.13±1.3 | <0.001 |
| WBC (×103/μL) | 7.45±2.5 | 7.17±2.4 | 7.43±2.4 | 7.49±2.4 | 7.53±2.5 | 7.63±2.8 | <0.001 |
| %Lymphocyte | 20.51±7.9 | 22.75±8.3 | 20.81±7.9 | 19.81±7.6 | 19.33±7.6 | 18.98±7.6 | <0.001 |
Note: Continuous variables expressed as mean ± SD; categorical variables expressed as number (percent); P-for trend shows the differences in each age categories.
Abbreviations: DM, diabetes mellitus; BMI, body mass index; nPNA, normalized protein nitrogen appearance; AVF, arteriovenous fistula; AVG, arteriovenous graft; COPD, chronic obstructive pulmonary disease; TIBC, total iron-binding capacity; Intact PTH, intact parathyroid hormone; WBC, white blood cells.