Endocrine Abstracts

Bone mineral disorders usually resolve after successful kidney transplantation. Serum calcium (Ca), phosphorus (P) and parathyroid hormone (PTH) levels tend to normalize within time. Serum Ca levels >10.2 mg/dL and PTH levels >150 pg/mL at 6th−12th months of transplantation is defined as persistent hypercalcemia and persistent hyperparathyroidism (PHPT) in recipients with normal graft function. Reported persistent hypercalcemia prevalence varies in wide range between 5% and 66%. This huge variation might be explained with different diagnostic criteria, heterogenic recipient population and variation in renal replacement vintage. We aimed to evaluate the prevalence of hypercalcemia and PHPT among recipients after successful kidney transplantation in our center.

Methods: We performed a retrospective study involving a total 391 (224 males, 40.6±11.9 years) adult kidney transplant recipients between January 2008 and December 2014. Recipients who were underwent parathyroidectomy before transplantation were excluded. Demographic and laboratory data of 307 recipients who were followed up at least 12 months were obtained by review of electronic file system. PHPT was defined as serum corrected Ca level >10.2 mg/dl (at least twice in a 6 month period) and PTH >150 pg/ml at 6th month of transplantation. Serum creatinine, Ca levels at pre- and post-transplant 1st, 3rd, 6th, 12th months, PTH levels at pre- and post-transplant 6th, 12th months of recipients were recorded.

Results: A total 307 recipients (150 deceased, 157 living donor; 175 male, 132 female; mean age 39.4±11.4 years) were enrolled the study. The mean duration of renal replacement treatment was 75.1±3.3 months. Mean serum Ca levels before transplantation and at 1st, 3rd, 6th, 12th months of transplantation were 9.3±0.8 mg/dl, 9.3±0.7 mg/dl, 9.6±0.7 mg/dl, 9.7±0.7 mg/dl, 9.7±0.7 mg/dl; and prevalence of hypercalcemia (>10.2 mg/dl) at 1st, 3rd, 6th, 12th months of transplantation were 10.8%, 21.2%, 21.2% and 21.2%, respectively. Mean serum PTH levels before transplantation and at 6th, 12th months of transplantation (>150 pg/ml) were 526.2±474.9 pg/ml, 237±334 pg/ml, 215±236.9 pg/ml, and prevalence of hyperparathyroidism at 6th, 12th months of transplantation were 57.1% and 52.3%, respectively.

Conclusion: PTH levels decreased and Ca levels remained stable after transplantation within 12 months in our study. Although prevalence of hyperparathyroidism was high, persistent hypercalcemia affected fewer recipients.