Table 1.
Baseline characteristics of the study participants.
| Variables | Total N = 656 |
Tertile 1 N = 219 < 75 pmol/24 h |
Tertile 2 N = 219 75–241.6 pmol/24 h |
Tertile 3 N = 218 > 241.6 pmol/24 h |
p-value |
|---|---|---|---|---|---|
| 24 h urinary vanin-1 excretion, pmol/24 h | 145 [51–331] | 34 [18–51] | 145 [104–192] | 488 [332–699] | |
| Clinical characteristics | |||||
| Female sex, n (%) | 283 (43.1) | 104 (47.5) | 95 (43.4) | 84 (38.5) | 0.2 |
| Age, years | 53 ± 13 | 51 ± 14 | 55 ± 12 | 54 ± 13 | 0.007 |
| BMI, kg/m2 | 26.6 ± 4.8 | 26.5 ± 5.1 | 26.1 ± 4.6 | 27.2 ± 4.7 | 0.067 |
| BSA, m2 | 1.94 ± 0.22 | 1.92 ± 0.23 | 1.92 ± 0.20 | 1.97 ± 0.22 | 0.035 |
| SBP, mmHg | 136 ± 18 | 136 ± 17 | 135 ± 17 | 138 ± 18 | 0.2 |
| Diabetes, n (%) | 158 (24.1) | 52 (23.7) | 60 (27.4) | 46 (21.1) | 0.3 |
| Hypertension. n (%) | 266 (40.7) | 89 (41.0) | 82 (37.4) | 95 (43.8) | 0.4 |
| History of cardiovascular disease, n (%) | 166 (25.3) | 53 (24.2) | 65 (29.7) | 48 (22.0) | 0.2 |
| Current smoking, n (%) | 76 (12.5) | 25 (12.0) | 20 (9.6) | 31 (16.1) | 0.1 |
| Transplant-related characteristics | |||||
| First kidney transplant, n (%) | 593 (90.5) | 201 (92.2) | 193 (88.1) | 199 (91.3) | 0.3 |
| Pre-emptive transplant, n (%) | 101 (15.4) | 38 (17.4) | 38 (17.4) | 25 (11.5) | 0.1 |
| Time after transplantation, years | 5.4 [2–12] | 5.2 [2–10.2] | 5.3 [1.6–12.1] | 6.1 [2.34–13.7] | 0.3 |
| Donor age, years | 43 ± 15 | 42 ± 15 | 44 ± 15 | 41 ± 16 | 0.2 |
| Living donor, n (%) | 220 (33.5) | 70 (32.0) | 76 (34.7) | 74 (33.9) | 0.8 |
| Positive HLA class I antibodies, n (%) | 98 (14.9) | 34 (15.5) | 34 (15.5) | 30 (13.8) | 0.8 |
| Positive HLA class II antibodies, n (%) | 111 (16.9) | 41 (18.7) | 30 (13.7) | 40 (18.3) | 0.3 |
| Cold ischemia time, hours | 15.5 [2.9–21.3] | 15.5 [3–22] | 15.6 [2.8–21] | 15.1 [2.7–21.7] | 0.5 |
| History of delayed graft function, n (%) | 48 (7.3) | 14 (6.4) | 18 (8.2) | 16 (7.3) | 0.8 |
| History of rejection, n (%) | 173 (26.4) | 48 (21.9) | 61 (27.9) | 64 (29.4) | 0.2 |
| Immunosuppressive medication | |||||
| Daily prednisolone dose, mg/24 h | 10.0 [7.5–10.0] | 10.0 [7.5–10.0] | 10.0 [7.5–10.0] | 10.0 [7.5–10.0] | 0.5 |
| Calcineurin inhibitor, n (%) | 378 (57.6) | 112 (51.1) | 132 (60.3) | 134 (61.5) | 0.057 |
| Proliferation inhibitor, n (%) | 543 (82.8) | 192 (87.7) | 186 (84.9) | 165 (75.7) | 0.002 |
| mTOR inhibitor, n (%) | 22 (3.4) | 8 (3.7) | 6 (2.7) | 8 (3.7) | 0.8 |
| Laboratory measurements | |||||
| Hb, mmol/L | 8.2 ± 1.1 | 8.2 ± 1.1 | 8.2 ± 1.1 | 8.3 ± 1.1 | 0.4 |
| HbA1c, % | 5.8 [5.5–6.2] | 5.7 [5.5–6.2] | 5.8 [5.5–6.3] | 5.8 [5.5–6.2] | 0.3 |
| Total cholesterol, mmol/L | 5.12 ± 1.14 | 5.11 ± 1.15 | 5.03 ± 1.17 | 5.23 ± 1.08 | 0.2 |
| LDL cholesterol, mmol/L | 2.98 ± 0.94 | 3.01 ± 0.97 | 2.87 ± 0.94 | 3.07 ± 0.90 | 0.081 |
| HDL cholesterol, mmol/L | 1.3 [1.1–1.6] | 1.3 [1.1–1.6] | 1.3 [1.1–1.7] | 1.3 [1.0–1.7] | 0.7 |
| Triglycerides, mmol/L | 1.68 [1.25–2.28] | 1.67 [1.15–2.26] | 1.62 [1.24–2.24] | 1.76 [1.29–2.33] | 0.2 |
| Serum ferritin, µg/mL | 121 [55–226] | 110 [56–201] | 109 [52–235] | 129 [59–229] | 0.4 |
| TSAT, % | 25.2 ± 10.7 | 24.8 ± 11 | 24.8 ± 10.9 | 25.9 ± 10.3 | 0.5 |
| hs-CRP, mg/L | 1.6 [0.7–4.7] | 1.6 [0.8–5.3] | 1.5 [0.6–4.6] | 1.7 [0.8–4.5] | 0.6 |
| Kidney function and glomerular injury parameters | |||||
| Serum creatinine, µmol/L | 123 [99–160] | 117 [96–148] | 126 [101–164] | 128 [105–164] | 0.030 |
| eGFR, mL/min/1.73 m2 | 52.8 ± 20.5 | 55.8 ± 21.7 | 51 ± 19.8 | 51.4 ± 19.8 | 0.024 |
| Urinary albumin excretion, mg/24 h | 38 [11–176] | 27 [8–111] | 43 [10–161] | 58 [13–386] | < 0.001 |
| Urinary protein excretion, g/24 h | 0.21 [0.01–0.37] | 0.16 [0.01–0.29] | 0.21 [0.01–0.35] | 0.24 [0.01–0.64] | < 0.001 |
| Tubular injury markers | |||||
| Urinary L-FABP excretion, µg/24 h | 2.07 [0.90–7.07] | 1.88 [0.85–5.34] | 2.06 [0.84–9.15] | 2.61 [1.08–7.99] | 0.055 |
| Urinary PTM-FetA excretion, µg/24 h | 32.9 [17.1–73.2] | 26.4 [14.1–62.5] | 34.8 [18.6–69.3] | 37.4 [18.4–89.4] | 0.057 |
| Urinary EGF excretion, µg/24 h | 9.43 [4.71–19.3] | 10.41 [5.63–21.46] | 8.71 [4.22–16.34] | 9.59 [4.61–17.53] | 0.2 |
| Plasma NGAL, µg/L | 170 [132–232] | 162 [126–228] | 166 [132–223] | 180 [137–242] | 0.2 |
| Tubular injury agents | |||||
| Urinary sC5b-9 excretion, µg/24 h | 5.09 [4.02–6.53] | 4.84 [3.77–5.9] | 5.11 [3.96–6.18] | 5.28 [4.37–8.15] | 0.002 |
| Urinary copper excretion, µg/24 h | 23.2 [15.6–35.3] | 21.9 [14.8–31.7] | 21.5 [14.8–33.3] | 25.4 [18.4–40.8] | < 0.001 |
Smoking status was missing in 47 (7.2%) patients, HbA1C was missing in 29 (4.4%) patients, hs-CRP was missing in 41 (6.2%) patients, urinary L-FABP was missing in 40 (6.1%) patients, urinary EGF was missing in 51 (7.8%) patients, and urinary PTM-FetA and urinary sC5b-9 was missing in 62 (9.5%) patients.
BMI, body mass index; BSA, body surface area; EGF, epidermal growth factor; eGFR, estimated glomerular filtration rate according to creatinine-based CKD-EPI formula; HbA1c, hemoglobin A1c; hs-CRP, high-sensitivity C-reactive protein; HLA, human leucocyte antigen; L-FABP, liver type-fatty acid binding proteins; mTOR, mechanistic target of rapamycin; NGAL, Neutrophil gelatinase-associated lipocalin; PTM-FetA, post-translationally modified fetuin-A protein; SBP, systolic blood pressure; sC5b-9, soluble C5b-9; TSAT, transferrin saturation.
Significant values are in bold.