RENAL TRANSPLANTATION IMPROVES PARATHYROID FUNCTION BUT DOES NOT CORRECT VITAMIN D DEFICIENCY

KIDNEY - CHRONIC GRAFT INJURY

R. Marcén, S. Jimenez-alvaro, F.J. Villacorta, A. Fernández-rodriguez, C. Galeano, J.J. Villafruela, J.L. Teruel, F.J. Burgos, C. Quereda
Nephrology, Hospital Ramón y Cajal, Madrid/SPAIN

Body: Introduction: Persistent hyperparathyroidism has been previously reported after renal transplantation. However, most of these studies are cross-sectional or have a short follow-up. Deficiency of vitamin D is also common in renal transplant recipients but there are few studies about the natural evolution of this disorder. The aims of the present study was to prospectively evaluate the calcium-phosphate metabolism parameters during 3 years after transplantation. Patients and methods: 182 renal transplant recipients with a functioning graft at 12 months were included in the study. Donor and recipient-related data at the time of transplantation as well as graft function and calcium-phosphate metabolism parameters including; serum calcium and phosphate, intact parathyroid hormone (iPTH), calcidiol (25OHD), calcitriol (1,25OHD) and tubular reabsorption of phosphorus (TRP) at 1,3,6,12,24 and 36 months were prospectively collected. Results: Data at 3, 12 and 36 months are expressed at the table 1:

Variable	3 months	12 months	36 months
Creatinine (mg/dL)	1.7±0.6	1.6±0.6	1.6±0.5
Calcium (mg/dL)	9.3±0.9	9.5±0.7	9.4±1.0
Calcium>10.2g/dL	10.2%	15.2%	12.8%
Phosphate (mg/dL)	2.8±0.5	3.0±0.6***	3.1±0.7***
iPTH (pg/mL)	180±189	166±134*	152±131**
iPTH >150 pg/mL	43.2%	40.0%	24.7%
25OHD (ng/ml)	24.2±14.6	22.3±13.0	20.5±10.5*
25OHD<16 ng/mL	32.6%	34.0%	43.5%
1,25OHD (pg/mL)	28.6±28.4	31.8±21.9	40.8±27.2**
1,25OHD<20pg/mL	49.5%	36.8%	31.3%

*p<0.05;**p<0.01 and *** p<0.001 vs 3 months There was an increase in the serum phosphate levels from 3 to 12 and 36 months and a progressive decrease in the iPTH and 1,25OHD concentrations. In the univariate analysis, iPTH levels at 12 months were related with time on dialysis, iPTH at 1 month, serum creatinine, serum albumin and serum phosphate at 12 months. Only time on dialysis, iPTH at 1 month and serum creatinine remained in the multivariate analysis. Conclusions: Pre-transplant hyperparathyroidism improved after successful renal transplantation but after 3 years an important number of patients had high iPTH levels. Calcidiol levels kept low and unchanged through the length of the follow-up, and most patiens had vitamin D insufficiency or deficiency. Our data suggest that vitamin D3 supplements should be administrated soon after transplantation.

Disclosure: All authors have declared no conflicts of interest.