Natural history of mineral and bone disorders after living-donor kidney transplantation: a one-year prospective observational study.

Mineral and bone disorders (MBD), including hypercalcemia and hypophosphatemia, are common complications after renal transplantation; however, the natural course of these disorders has not been well documented, and the pathogenesis of persistent post-transplant MBD still remains elusive. This study was carried out to show the natural history of mineral metabolism in recipients after living-donor kidney transplantation and also to clarify post-transplant risk factors of persistent hypercalcemia and/or hypophosphatemia at 12months after transplantation. Living-donor kidney transplant recipients (N=34) at Tokyo Women's Medical University were prospectively and consecutively recruited. Parameters of MBD, including intact parathyroid hormone and full-length fibroblast growth factor23, were followed. Serum calcium levels increased until the fourth week post-transplantation, after which it reached a plateau; and serum phosphate decreased substantially at one week post-kidney transplantation, but recovered to the reference level at two months. Fibroblast growth factor23 gradually decreased to comparable levels for renal function, while hyperparathyroidism persisted for 12months after transplantation. Multivariate linear regression analysis revealed that intact parathyroid hormone was the best correlating factor with both hypercalcemia and persistent hypophosphatemia at 12months. This study suggests the need for testing of other interventions used for treatment of hyperparathyroidism which may help to offer better management of MBD after kidney transplantation.