Table 1.
Baseline facility- and patient-level characteristics in the STEPPS study by dialysis facility 25% and 100% opt-in status
| BASELINE CHARACTERISTICS N (%); mean ± SD | 25% (n = 346, 12 facilities) | 100% (n = 1296, 37 facilities) | p-value | |Standardized Difference| |
|---|---|---|---|---|
| Facility-level characteristics | ||||
| South (vs.non-South) geographic region | 5 (41.7) | 17 (45.9) | 0.80 | 0.09 |
| Urban (vs.rural) | 10 (83.3) | 28 (75.7) | 0.71 | 0.19 |
| For profit status | 12 (100.0) | 30 (81.1) | 0.17 | 0.68 |
| Percent Medicare primary payer | 78.1 ± 14.9 | 64.0 ± 17.6 | 0.02 | 0.86d |
| Patient-level characteristics | ||||
| Age (years) | 60.6 ± 15.6 | 61.6 ± 14.9 | 0.29 | 0.06 |
| Male sex | 201 (58.1) | 738 (56.9) | 0.70 | 0.02 |
| Race | ||||
| White | 130 (37.6) | 743 (57.3) | 0.00 | 0.42d |
| Black | 137 (39.6) | 303 (23.4) | ||
| Other/Unknown | 79 (22.8) | 250 (19.3) | ||
| Primary Cause of CKD | ||||
| Diabetes | 151 (43.6) | 604 (46.6) | 0.05 | 0.15 |
| Hypertension | 110 (31.8) | 328 (25.3) | ||
| Other/unknown | 85 (24.6) | 364 (28.1) | ||
| BMI (kg/m2) | 28.6 ± 6.7 | 29.2 ± 7.7 | 0.16 | 0.08 |
| Years on dialysis | 4.1 ± 3.7 | 3.1 ± 3.1 | <0.0001 | 0.29d |
| Medical History | ||||
| Congestive Heart Failure | 111 (32.1) | 359 (27.7) | 0.11 | 0.10 |
| Hypertension | 288 (83.2) | 1121 (86.5) | 0.12 | 0.09 |
| Diabetes | 148 (42.8) | 623 (48.1) | 0.08 | 0.11 |
| Cancer (other than skin) | 31 (9.0) | 157 (12.1) | 0.10 | 0.10 |
| Vascular access typea | ||||
| Arteriovenous fistula/graft | 287 (82.9) | 1013 (78.3) | 0.06 | 0.12 |
| Venous catheter | 59 (17.1) | 281 (21.7) | ||
| Laboratory values a | ||||
| Hemoglobin (g/dL) | 11.3 ± 1.3 | 11.2 ± 1.3 | 0.26 | 0.07 |
| Hemoglobin group | ||||
| <10 g/dL | 41 (11.8) | 194 (15.0) | 0.15 | 0.12 |
| 10 – 12 g/dL | 204 (59.0) | 784 (60.5) | ||
| ≥12 g/dL | 99 (28.6) | 317 (24.5) | ||
| PTH (pg/dL) | 443.0 ± 344.3 | 358.4 ± 306.8 | <0.0001 | 0.26e |
| Calcium (mg/dL) | 8.9 ± 0.8 | 9.0 ± 0.7 | 0.02 | 0.14 |
| Phosphorus (mg/dL) | 5.3 ± 1.6 | 5.3 ± 1.6 | 0.68 | 0.03 |
| TSAT (%) | 28.7 ± 11.0 | 31.4 ± 12.3 | <0.0001 | 0.23e |
| Ferritin (ng/mL) | 642.6 ± 388.2 | 754.7 ± 466.8 | <0.0001 | 0.26e |
| Albumin (g/dL) | 3.8 ± 0.4 | 3.8 ± 0.4 | 0.44 | 0.05 |
| ESA administration a,b | ||||
| EPO monthly dose (units) | 62471 ± 61748 | 53655 ± 55605 | 0.02 | 0.15 |
| IV (vs. SC) ESA route | 299 (92.6) | 1092 (92.0) | 0.74 | 0.02 |
| Other medications c | ||||
| Iron use | ||||
| IV only | 239 (69.1) | 891 (68.8) | 0.69 | 0.08 |
| Oral only | 1 (0.3) | 11 (0.8) | ||
| Both IV and Oral | 5 (1.4) | 17 (1.3) | ||
| No iron use | 101 (29.2) | 377 (29.1) | ||
| Vitamin D use | ||||
| IV only | 284 (82.1) | 949 (73.2) | <0.0001 | 0.32e |
| Oral only | 0 (0.0) | 37 (2.9) | ||
| Both IV and Oral | 9 (2.6) | 78 (6.0) | ||
| No Vitamin D use | 53 (15.3) | 232 (17.9) | ||
| Cinacalcet use | 82 (23.7) | 294 (22.7) | 0.69 | 0.02 |
| Phosphate binder use | 232 (67.1) | 791 (61.0) | 0.04 | 0.13 |
aLast non-missing value in the baseline period; bAmong ESA users; cWithin the baseline period; dTime-invariant variable evaluated as potential confounder in parsimonious modeling; eTime-variant variable not evaluated as potential confounder in parsimonious modeling.
BMI, body mass index; TSAT, transferrin saturation; PTH, parathyroid hormone; EPO, epoetin alfa; IV, intravenous; SC, subcutaneous.