Mineral Bone Disorders after Preemptive Kidney Transplantation

Background: Mineral bone disorders are common after kidney transplantation. Preemptive kidney transplantation (PKT) may reduce these risks. We aimed to assess the long-term effects of PKT on mineral metabolism outcomes Methods: Retrospective cohort study with a median follow-up time of 4 years (range 1-9). We compared kidney transplant recipients (KTRs) who underwent PKT (n=26) with KTRs who received hemodialysis before transplantation (n=359). The outcomes included iPTH, free calcium, phosphate, and eGFR trajectories, as well as the presence of post-transplant persistent hyperparathyroidism (iPTH > upper reference level), persistent hypercalcemia (free Ca >5.2 mg/dL) and graft dysfunction (<30 mL/min/1.73m2). Asymptomatic mild hypercalcemia was monitored unless complications developed Results: Pre-transplant iPTH levels were similar between the PKT and non-PKT groups (median 479 [238-828] Vs 392 [145-603]; p=0.064). There were no differences in the trajectory of biochemical parameters between groups after transplantation. Similarly, when comparing PKT and non-PKT KTRs, we observed no differences in persistent hyperparathyroidism (39% Vs. 45%, P=0.54), persistent hypercalcemia (73% Vs. 62%, p=0.17), and graft dysfunction (4% Vs. 6%, p=0.58). In both groups, PTH levels below 300 were a protective factor against the development of post-transplant hyperparathyroidism or hypercalcemia Conclusion: PKT in KTRs without controlled hyperparathyroidism did not decrease the risk of hyperparathyroidism or persistent hypercalcemia after transplantation. Medical treatment of mineral bone disorders, with a target iPTH below 300, likely decreases the risk of adverse outcomes in KTRs, including individuals undergoing PKT