FGF23 is associated with early post-Transplant hypophosphataemia and normalizes faster than iPTH in living donor renal transplant recipients: A longitudinal follow-up study

Abstract

Background: We aimed to longitudinally analyse changes in the levels of serum fibroblast growth factor 23 (FGF23), intact parathyroid hormone (IPTH) and associated minerals in patients undergoing renal transplantation. Methods: Sixty-Three patients with end-stage renal disease (ESRD) who underwent living donor transplantationwere recruited. SerumFGF23, IPTH, uric acid, inorganic phosphorous (IP), blood urea nitrogen and serumcreatinineweremeasured pre-Transplant and at 1 (M1), 3 (M3) and 12 months (M12) post-Transplantation. Results: FGF23 levels were decreased at M1, M3 and M12 by 93.81, 96.74 and 97.53%, respectively. IPTH levels were decreased by 67.95, 74.95 and 84.9%, respectively. The prevalence of hyperparathyroidism at M1, M3 and M12 post-Transplantation was 63.5, 42.9 and 11.1%, respectively. FGF23 and IP levels remained above the normal range in 23 (36.5%) and 17 (27%) patients at M1, 10 (15.9%) and 5 (8%) at M3 and in none at M12 post-Transplantation, respectively. A multivariate regression model revealed that, pre-Transplant, IP was positively associated with IPTH (P = 0.016) but not with FGF 23; however, post-Transplant, IP level was negatively associated with FGF23 (P < 0.001) but not with IPTH. Conclusions: Post-Transplant FGF23 levels settle faster than those of IPTH. However, 11% of patients continued to have hyperparathyroidism even after 12 months.