Table 1.
Baseline characteristics of the overall study population and according to tertiles of FGF23
| FGF23 (RU/ml) |
Pa | ||||
|---|---|---|---|---|---|
| All Patients (n = 984) 28 (20, 43) | FGF23 Tertile 1 (n = 328) 18 (15, 20) | FGF23 Tertile 2 (n = 328) 28 (26, 32) | FGF23 Tertile 3 (n = 328) 55 (43, 86) | ||
| Age, years | 51 ± 13 | 49 ± 13 | 50 ± 13 | 54 ± 12 | <0.01 |
| Male (%) | 57 | 56 | 59 | 56 | 0.6 |
| Etiology of kidney disease (%) | 0.3 | ||||
| glomerulonephritis | 23 | 23 | 25 | 20 | |
| tubulointerstitial nephritis | 13 | 15 | 12 | 13 | |
| polycystic kidney disease | 18 | 15 | 16 | 23 | |
| diabetes | 4 | 6 | 5 | 3 | |
| hypertension | 7 | 6 | 7 | 6 | |
| other or unknown | 35 | 35 | 35 | 35 | |
| Dialysis duration, months | 20 (9, 38) | 19 (9, 41) | 19 (9, 39) | 21 (9, 36) | 1.0 |
| Deceased donor transplant (%) | 96 | 96 | 95 | 97 | 0.6 |
| Delayed graft function (%) | 26 | 24 | 24 | 30 | 0.1 |
| History of acute rejection (%) | 35 | 32 | 32 | 40 | 0.05 |
| Transplant vintage, months | 72 (40, 114) | 62 (35, 103) | 66 (35, 107) | 91 (51, 127) | <0.01 |
| Body mass index, kg/m2 | 27 ± 5 | 27 ± 5 | 27 ± 5 | 26 ± 5 | <0.01 |
| Systolic BP, mmHg | 142 ± 19 | 140 ± 19 | 140 ± 18 | 145 ± 20 | <0.01 |
| Diastolic BP, mmHg | 84 ± 12 | 84 ± 12 | 83 ± 12 | 85 ± 13 | 0.4 |
| Current smoker (%) | 19 | 17 | 20 | 18 | 0.5 |
| Charlson comorbidity index | 2 (2, 4) | 2 (2, 3) | 2 (2, 3) | 2 (2, 4) | 0.02 |
| Laboratory results | |||||
| creatinine, mg/dl | 1.4 (1.2, 1.8) | 1.2 (1.0, 1.5) | 1.4 (1.1, 1.7) | 1.8 (1.4, 2.3) | <0.01 |
| eGFR, ml/min per 1.73 m2 | 51 ± 21 | 61 ± 19 | 53 ± 19 | 39 ± 19 | <0.01 |
| eGFR > 60 ml/min per 1.73 m2 | 32 | 50 | 32 | 13 | <0.01 |
| eGFR 30 to 60 ml/min per 1.73 m2 | 51 | 47 | 56 | 50 | <0.01 |
| eGFR < 30 ml/min per 1.73 m2 | 17 | 3 | 12 | 37 | <0.01 |
| albumin, g/dl | 4.0 ± 0.4 | 4.1 ± 0.4 | 4.1 ± 0.4 | 3.9 ± 0.5 | <0.01 |
| calcium, mg/dl | 9.4 ± 0.6 | 9.5 ± 0.5 | 9.5 ± 0.6 | 9.4 ± 0.8 | 0.01 |
| phosphate, mg/dl | 3.3 ± 0.9 | 3.2 ± 0.9 | 3.2 ± 0.6 | 3.6 ± 1.0 | <0.01 |
| 25-hydroxyvitamin D, ng/ml | 11.2 ± 7.6 | 11.9 ± 7.9 | 11.1 ± 7.6 | 10.5 ± 7.2 | 0.04 |
| parathyroid hormone, pg/ml | 68 (48, 103) | 59 (43, 83) | 70 (50, 101) | 85 (54, 150) | <0.01 |
| hemoglobin, g/dl | 13.5 ± 1.7 | 13.7 ± 1.4 | 13.7 ± 1.6 | 13.0 ± 1.9 | <0.01 |
| white blood cells (cells × 103) | 7.9 ± 2.3 | 7.9 ± 2.2 | 7.8 ± 2.2 | 7.9 ± 2.6 | 0.6 |
| C-reactive protein (mg/L) | 3.1 (1.5, 6.8) | 2.9 (1.5, 6.7) | 3.1 (1.5, 7.2) | 3.6 (1.4, 6.7) | 0.7 |
| FGF23-modifying therapies | |||||
| 1,25-dihydroxyvitamin D (%) | 33 | 28 | 32 | 40 | <0.01 |
| dietary phosphate binders (%) | 6 | 4 | 4 | 9 | <0.01 |
| Immune suppression agents (%) | |||||
| steroids | 81 | 75 | 81 | 88 | <0.01 |
| calcineurin inhibitor | 90 | 91 | 91 | 89 | 0.7 |
| mycophenolate mofetil | 78 | 82 | 81 | 71 | 0.01 |
| sirolimus | 8 | 9 | 7 | 7 | 0.6 |
Values reported as %, means ± SD, or median (interquartile range) as appropriate.
aP represents tests of significance from one-way ANOVA, Kruskal-Wallis, or χ2 tests.