Incidence, risk factors and survival outcomes of post-transplant tertiary hyperparathyroidism in kidney recipients

Table 1 Characteristics of the study cohort according to the occurrence of post-transplant tertiary hyperparathyroidism, n (%)

Characteristics	PT-tHPT (n = 125)	Non-tHPT (n = 762)	Total (n = 887)	P value
Demographics
Age (years), mean (SD)	50.5 (13.2)	47.0 (15.5)	47.5 (15.2)	0.016
Sex				0.617
Male	74 (59.2)	469 (61.5)	543 (61.2)
Female	51 (40.8)	293 (38.5)	344 (38.8)
Ethnicity				0.028
White	110 (88.0)	609 (79.9)	719 (81.1)
Asian	11 (8.8)	125 (16.4)	136 (15.3)
Black	4 (3.2)	12 (1.6)	16 (1.8)
Other	0 (0.0)	16 (2.1)	16 (1.8)
Pretransplant body mass index, mean (SD)	27.4 (5.0)	27.0 (8.3)	27.1 (7.9)	0.634
Donor characteristics
Donor type category				0.006
Deceased donor	101 (80.8)	523 (68.7)	624 (70.4)
Living donor	24 (19.2)	238 (31.3)	262 (29.6)
Total human leucocyte antigen mismatch, median (IQR)	3.0 (2.0-3.0)	3.0 (2.0-3.0)	3.0 (2.0-3.0)	0.425
Total ischaemia time, mean (SD)	14.1 (7.1)	12.5 (7.7)	12.7 (7.6)	0.037
Recipients’ characteristics
Primary renal disease				0.033
Adult polycystic kidney disease	12 (9.6)	104 (13.6)	116 (13.1)
Glomerulonephritis	32 (25.6)	207 (27.2)	239 (26.9)
Diabetic kidney disease	9 (7.2)	99 (13.0)	108 (12.2)
Hypertensive kidney disease	8 (6.4)	52 (6.8)	60 (6.8)
Reflux/chronic pyelonephritis	28 (22.4)	90 (11.8)	118 (13.3)
Unknown	21 (16.8)	130 (17.1)	151 (17.0)
Other	15 (12.0)	80 (10.5)	95 (10.7)
Dialysis vintage (pre-emptive transplants excluded), median (IQR)	39.0 (20.0-63.0)	23.0 (11.0-38.0)	25.0 (12.0-44.0)	< 0.001
Pretransplant diabetes	20 (16.0)	136 (17.8)	156 (17.6)	0.615
Transplant number, mean (SD)	1.2 (0.5)	1.1 (0.4)	1.1 (0.4)	0.013
Pre-emptive transplant	24 (19.8)	246 (34.2)	270 (32.1)	0.002
Pre-transplant calcium (mmol/L), median (IQR)	2.5 (2.4-2.5)	2.3 (2.2-2.4)	2.3 (2.2-2.4)	< 0.001
Pre-transplant phosphate (mmol/L), median (IQR)	1.6 (1.4-1.9)	1.6 (1.3-1.9)	1.6 (1.4-1.9)	0.153
Pre-transplant PTH (ng/L), median (IQR)	415.8 (232.0-717.9)	185.0 (97.8-307.8)	202.0 (107.0-360.0)	< 0.001
Post-transplant PTH (ng/L), median (IQR)	135.8 (107.6-240.1)	83.7 (58.3-119.9)	88.4 (61.7-138.1)	< 0.001
Smoking history				0.073
Non-smoker	110 (92.4)	604 (86.5)	714 (87.4)
Current smoker	9 (7.6)	94 (13.5)	103 (12.6)
Immunosuppression regime
Main immunosuppression				0.557
Tacrolimus	110 (88.7)	674 (90.1)	784 (89.9)
Mammalian target of rapamycin inhibitor	3 (2.4)	9 (1.2)	12 (1.4)
Cyclosporin	11 (8.9)	65 (8.7)	76 (8.7)
Antimetabolite				0.739
None	14 (11.3)	80 (10.7)	94 (10.8)
Mycophenolic acid	97 (78.2)	571 (76.3)	668 (76.6)
Azathioprine	13 (10.5)	97 (13.0)	110 (12.6)
Steroid regime				0.016
< 6 monhs of glucocorticoid	54 (45.4)	405 (57.2)	459 (55.5)
> 6 months of glucocorticoid	65 (54.6)	303 (42.8)	368 (44.5)
Other
Baseline eGFR (mL/minute/1.73 m2), median (IQR)	50.0 (37.2-62.2)	51.0 (40.8-65.0)	51.0 (40.0-64.0)	0.373
History of acute rejection	20 (16.5)	78 (10.9)	98 (11.7)	0.074
The eGFR slope (mL/minute/year), median (IQR)	1.4 (3.20.0)	0.8 (2.70.5)	0.9 (2.70.5)	0.027

Continuous variables: Presented as mean (SD) or median (interquartile range) and compared using the independent t-test test or Wilcoxon’s sign-rank test. Categorical variables: Presented as n (%) and compared using Pearson’s χ² test. eGFR: Estimated glomerular filtration rate; IQR: Interquartile range; PTH: Parathyroid hormone; PT-tHPT: Post-transplant tertiary hyperparathyroidism; tHPT: Tertiary hyperparathyroidism.