Table 1.
Patient characteristics categorized by the median EPO level.
| Variables | All patients | Low EPO | High EPO | P value |
|---|---|---|---|---|
| n | 290 | 145 | 145 | |
| EPO, IU/L | 14.4 (10.2–22.8) | 10.2 (8.4–12.1) | 22.8 (17.9–33.6) | <0.01 |
| Age, years | 71 (64–77) | 70 (63–76) | 72 (66–78) | 0.04 |
| Male sex | 176 (61) | 88 (61) | 88 (61) | 1.00 |
| BMI, kg/m2 | 23.5 (21.1–26.8) | 23.1 (20.7–25.8) | 23.9 (21.5–27.8) | 0.04 |
| History of CVD | 135 (47) | 61 (42) | 74 (51) | 0.13 |
| Diabetic retinopathy | 119 (41) | 68 (47) | 51 (35) | 0.04 |
| Smoking | 44 (15) | 20 (14) | 24 (17) | 0.51 |
| SBP, mmHg | 130 (122–138) | 129 (122–138) | 130 (122–137) | 0.73 |
| Hemoglobin A1c, % | 6.9 (6.3–7.4) | 6.9 (6.4–7.4) | 6.9 (6.3–7.5) | 0.75 |
| LDL-cho, mg/dL | 95 (79–116) | 98 (79–116) | 95 (78–117) | 0.82 |
| eGFR, mL/min/1.73 m2 | 53 (40–67) | 49 (40–63) | 56 (40–71) | 0.08 |
| Corrected Ca, mg/dL | 9.2 (9.0–9.4) | 9.3 (9.0–9.4) | 9.2 (9.0–9.4) | 0.93 |
| Albumin, g/dL | 4.1 (3.9–4.4) | 4.2 (3.9–4.4) | 4.1 (3.8–4.3) | 0.04 |
| CRP, mg/dL | 0.06 (0.01–0.15) | 0.06 (0.01–0.11) | 0.06 (0.01–0.22) | 0.12 |
| Hemoglobin, g/dL | 11.8 (11.0–12.5) | 11.9 (11.5–12.6) | 11.4 (10.8–12.4) | <0.01 |
| TSAT, % | 23.4 (15.9–31.1) | 25.9 (20.2–32.1) | 19.7 (10.9–29.1) | <0.01 |
| Ferritin, ng/dL | 69 (26–214) | 88 (46–141) | 32 (14–103) | <0.01 |
| UACR, mg/g Cre | 60 (16–320) | 74 (20–359) | 47 (14–276) | 0.11 |
| u-LFABP, mg/g Cre | 5.1 (2.3–14.2) | 5.6 (2.5–15.7) | 4.4 (2.1–11.8) | 0.17 |
| FGF23, pg/mL | 32 (27–45) | 34 (27–49) | 33 (27–42) | 0.31 |
| 25D, ng/mL | 8 (5–13) | 9 (5–13) | 7 (5–14) | 0.31 |
| ACEI/ARB | 177 (61.0) | 93 (64.1) | 84 (57.9) | 0.28 |
| Statin | 113 (40) | 61 (42) | 52 (37) | 0.34 |
| Insulin | 150 (53) | 77 (54) | 73 (52) | 0.77 |
| OHA | 213 (74.7) | 103 (71.0) | 110 (75.9) | 0.35 |
| Outcome | ||||
| eGFR slope, mL/min/1.73 m2/year | −1.3 (−3.6–1.0) | −1.7 (−4.0–0.4) | −0.8 (−3.3–1.4) | 0.02 |
Data are expressed as median (interquartile range) or n (%). EPO, erythropoietin; BMI, body mass index; CVD, cardiovascular disease; SBP, systolic blood pressure; eGFR, estimated glomerular filtration rate; Ca, calcium; CRP, C-reactive protein; TSAT, transferrin saturation; Cre, urine creatinine; UACR, urine albumin-to-creatinine ratio; u-LFABP, urinary liver-type fatty acid-binding protein; FGF23, fibroblast growth factor 23; 25D, 25-hydroxyvitamin D; ACEI/ARB, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers; OHA, oral hypoglycemic agents.