Natural History of Serum Calcium and Parathyroid Hormone Following Renal Transplantation

Background. Hyperparathyroidism is common in end-stage renal disease. It often persists following renal transplantation (RTx) and remains elusive to manage due to the lack of evidence base. We therefore present observational data describing the natural history and management of hypercalcemia and hyperparathyroidism following RTx. Methods. Single-center experience of 216 adult patients undergoing kidney transplantation between January 1, 2011, and December 31, 2012. Data included calcium and parathyroid hormone (PTH) pretransplant and post-transplant at 1, 13, 26, and 52 weeks. Hyperparathyroidism management modalities were also noted. Results. Persistent hyperparathyroidism (secondary/tertiary) following transplantation was observed in 71 (32.9%) patients. Mean PTH level decreased in the first 3 months post-RTx (3.95 +/- 0.14 vs 3.61 +/- 0.13 pmol/L; P < .01). Thereafter it remained relatively static until 1 year post-RTx (3.39 +/- 0.14 pmol/L). Mean adjusted calcium level rose in the 3 months post-RTx and then remained largely unchanged until 1 year (2.39 +/- 0.2 mmol/L, 2.49 +/- 0.21 mmol/L, 2.47 +/- 0.23 mmol/L at pretransplant, 3 months, and 12 months, respectively). Cinacalcet use pretransplant was significantly associated with reduced post-transplant hyperparathyroidism (15% vs 4.7% respectively, P = .006). There was no association between PTH (3.62 +/- 4.16 mmol/L) or adjusted calcium levels (2.51 +/- 17 mmol/L) at 6 months and estimated glomerular filtration rate at 1 year (r(2) = 0.16 and r(2) = 0.23, respectively). Conclusion. Tertiary hyperparathyroidism following RTx is common. However, no association was observed between either post-transplant PTH or adjusted calcium and graft function.