Evaluation of Serum Level of FGF23 and 1,25(OH)(2)D(3) in Primary Hyperparathyroidism Patients Before and After Parathyroidectomy

PURPOSE: Parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) play critical roles in phosphate homeostasis. To the best of our knowledge, there are limited data on the impact of FGF23 and PTH on serum calcium, 1,25(OH)(2)D(3), and phosphate in patients with primary hyperparathyroidism (PHPT). We examined these parameters and their correlations in PHPT patients before and after parathyroidectomy (PTX). PATIENTS AND METHODS: In this prospective cohort study, 29 PHPT patients who met the inclusion criteria were selected. The patient’s blood samples were taken three times: before the operation, 24 h after the operation, and 1 week after the operation. The concentrations of serum calcium, FGF23, 1,25(OH)(2)D(3), phosphate, PTH, and alkaline phosphatase were measured in a referral laboratory at each of the three steps. Moreover, 25(OH)D was primarily measured just before the surgery. RESULTS: Of 29 patients included in this study with a mean age of 52.37±12.3 years, majority were females (75.8%). Serum FGF23 and 1,25(OH)(2)D(3) levels were high before PTX and decreased after the operation; however, the difference was not statistically significant. FGF23 levels were significantly correlated with 1,25(OH)(2)D(3) at each of the three steps (r=0.964, P <0.01; r=0.985, P <0.0; and r=0.976, P <0.05). The variations in calcium, phosphate, creatinine, and PTH were preoperatively and postoperatively significant. CONCLUSION: Although 1,25(OH)(2)D(3) and FGF23 levels were preoperatively higher in PHPT, their variations were not meaningful. There was a statistically direct significant relationship between 1,25(OH)(2)D(3) and FGF23 preoperatively and postoperatively; however, the correlations between FGF23 and calcium, phosphate, and PTH were not significant.