Table 1.

Clinical characteristics of the cohort

VariableAll Patients, n=957Absent Hypophosphatemia, n=136Mild Hypophosphatemia, n=375Severe Hypophosphatemia, n=446P Value
Lowest serum phosphate post-Tx, mg/dl1.58 [1.30–1.95]2.45 [2.26–2.73]1.80 [1.67–1.98]1.24 [1.05–1.42]<0.001
Age, yr49 [39–59]49 [36–58]50 [39–58]49 [39–59]0.40
Men, n (%)557 (58)64 (47)221 (59)272 (61)0.02
Smoking status, n (%)
 Current smoking48 (5)5 (4)13 (4)30 (7)0.40
 No smoking488 (51)65 (48)188 (50)235 (52)
 Unknown421 (44)66 (49)174 (46)181 (41)
Etiology of kidney disease, %
 Primary glomerular disease24.626.824.920.90.44
 GN5.54.66.86.2
 Tubulointerstitial nephritis/pyelonephritis10.210.89.014.0
 Polycystic kidney disease18.420.218.416.3
 Renovascular8.59.28.87.0
 Diabetes4.13.74.74.7
 Dysplasia1.81.42.51.6
 Other/unknown24.123.424.929.5
Panel of reactive antibodies, %8.08.09.010.00.54
Donor type: living/cadaveric, n220/73728/10864/311128/318<0.001
Cold ischemia time, h17.8 [10.1–23.0]18.2 [11.7–24.4]19.0 [13.3–23.8]16.0 [3.0–22.9]<0.001
Warm ischemia time, min40 [33–50]40 [35–52]40 [33–51]39 [32–45]0.02
Delayed graft function, n (%)270 (28)50 (37)110 (29)110 (25)0.02
Preemptive, n (%)31 (3.2)8 (5.9)11 (2.9)12 (2.7)0.14
Dialysis vintage, mo39 [20–58]41 [18–62]40 [22–59]37 [20–57]0.56
Serum calcium pre-Tx, mg/dl9.62 (1.04)9.62 (1.12)9.70 (1.12)9.94 (0.92)0.14
Serum PTH pre-Tx, pg/ml160.3 [72.4–393.7]103.7 [61.1–212.2]122.6 [57.3–396.1]188.6 [88.2–393.7]0.04
Acute rejection, n (%)342 (36)47 (35)135 (36)160 (36)0.95
Time between Tx and lowest phosphate, d33 [21–51]35 [15–68]35 [22–53]32 [21–48]0.32
eGFR (CKD-EPI),a ml/min per 1.73 m252 [39–66]41 [26–54]49 [38–60]58 [46–70]<0.001
Phosphate supplementation, n (%)67 (7.0)7 (5.2)18 (4.8)42 (9.4)0.06
Vitamin D supplementation, n (%)176 (18.4)41 (30.1)57 (15.2)78 (17.5)<0.001
Vitamin D supplementation pre-Tx, n (%)399 (41.7)47 (34.6)149 (39.7)203 (45.5)0.25
Hypophosphatemia symptoms,b n (%)5 (0.5)1 (0.74)3 (0.8)1 (0.22)0.44
Serum calcium,a mg/dl9.22 (0.96)9.06 (1.04)9.38 (0.96)9.46 (0.96)<0.001
Corrected calcium,a mg/dl9.57 (0.82)9.32 (0.89)9.55 (0.78)9.67 (0.83)<0.001
Serum PTH,a pg/ml85.8 [61.5–137.8]69.5 [47.4–132.8]85.8 [70.0–129.5]91.3 [67.3–140.3]<0.001
Proteinuria,a g/24 h0.3 [0.2–0.6]0.2 [0.3–0.6]0.4 [0.2–0.7]0.2 [0.3–0.6]0.30
Albumin,a g/dl3.8 [3.4–4.1]3.6 [3.4–4.0]3.8 [3.4–4.2]3.8 [3.4–4.1]0.65
24-h Urea excretion,a mg/dl2673 [2100–3302]2611 [2131–3108]2701 [2098–3342]2673 [2092–3325]0.22
Medication use
 Cyclosporin use, %87.993.487.786.30.09
 Cyclosporin trough,a μg/L224 (165)209 (125)223 (144)230 (190)0.16
 Tacrolimus use, %7.42.97.58.70.08
 Tacrolimus trough,a μg/L11.1 (6.0)8.1 (4.9)11.6 (5.9)11.4 (6.2)0.56
 Proliferation inhibitor, %76.880.976.875.60.46
 mTOR inhibitor, %3.81.54.34.00.31
 Corticosteroids, %96.498.597.395.10.08
 Other, %23.426.524.321.70.46
Induction therapy, n (%)
 Antithymocyte globulin87 (9)10 (7)38 (10)39 (9)0.59
 Anti–IL-2 mAb410 (43)62 (45)152 (41)196 (44)0.48
 Other/unknown460 (48)64 (47)185 (49)211 (47)0.82
CMV-positive status376 (39.5)180 (40.5)141 (37.6)180 (40.5)0.74
Pre-Tx diabetes mellitus (no/DM1/DM2), %94/2/493/2/594/3/394/2/40.82
BMI at Tx, kg/m224.3 [22.0–27.2]23.7 [21.9–28.3]24.6 [22.0–27.1]24.3 [22.0–27.2]0.94
Pre-Tx CV event, n (%)111(11.9)9 (6.9)46 (12.8)56 (12.6)0.16
Systolic BP at 3 mo, mmHg140 [130–152]145 [130–160]140 [133–154]140 [130–150]0.18
Diastolic BP at 3 mo, mmHg85 [80–90]82 [80–90]85 [80–90]85 [80–94]0.14
Donor characteristics
 Age, yr47 [35–55]47 [38–54]47 [35–56]46 [33–54]0.65
 Men, n (%)477 (49.9)66 (48.5)197 (52.5)214 (48)0.41
 CMV-positive status, n (%)475 (49.9)76 (57.1)170 (45.3)229 (51.6)0.12
HLA mismatches, valid %
 A (0/1/2)47/46/743/48/949/45/645/47/80.35
 B (0/1/2)40/47/137/51/1343/44/1437/50/130.53
 DR (0/1/2)52/45/254/44/256/42/248/48/30.12
  • Data are presented as mean (SD) or median [first to third quartiles] unless otherwise noted. Tx, transplantation; PTH, parathyroid hormone; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; mTOR, mammalian target of rapamycin; CMV, cytomegalovirus; DM1, type 1 diabetes mellitus; DM2, type 2 diabetes mellitus; BMI, body mass index; CV, cardiovascular.

  • a Measured at the time of lowest serum phosphate level.

  • b Symptoms attributed to hypophosphatemia by treating nephrologist.