SP762
LONG TERM EVOLUTION OF THE MINERAL METABOLISM AFTER RENAL TRANSPLANTATION

INTRODUCTION AND AIMS: Abnormalities in bone and mineral metabolism are common after renal transplantation but information on their long-term time course is scarce. We evaluated the time course of biochemical parameters of mineral metabolism over 60 months after renal transplantation and identified predictors for persistent hyperparathyroidism.

METHODS: Between 2002 and 2012, we retrospectively analyzed medical records of 176 consecutive renal transplant patients. We collected data on serum levels of intact parathyroid hormone (iPTH), calcium (Ca), phosphorus (P) and creatinine (Cr) preoperatively and then at first week, 1, 3, 6, 9, 12, 24, 60 months after renal transplantation. We in addition recorded demographic, clinical, and therapeutic data.

RESULTS: Demographic and clinical characteristics of study participants are listed in Table 1. Pre-transplantation iPTH regressed from 415.3±422.6 to 164.6±203.8 pg/ml at 6 month. Baseline serum Ca stabilized from 9.1±1.0 to 9.6±0.7 mg/dl at 1 month. Baseline serum P stabilized from 5.4±1.6 to 3.3±0.6 mg/dl at 6 months. Stable graft function (1.3±0.5 mg/dl) was achieved from 6 months onward (Table 2). By 60 months, 13.5% of patients had serum Ca above 10.2 mg/dl; 11.7%, serum P below 2.5 mg/dl; and 17.8%, serum iPTH more than 2-fold the upper limit of normal. According to univariate analysis female sex, duration of dialysis, iPTH and Ca serum levels at the first post-transplant week were significantly associated with hyperparathyroidism at first year. However at multivariate logistic regression only first week hypercalcemia remained significantly associated with first year hyperparathyroidism.

CONCLUSIONS: Hypercalcemia, hypophosphatemia, and elevated iPTH persist in a subset of post-renal transplantation patients. Hypercalcemia in the early post-transplant period seems to be a risk factor for persistent hyperparathyroidism.