Perioperative changes of FGF23 in patients undergoing surgery for primary hyperparathyroidism

Abstract

Background: Fibroblast growth factor-23 (FGF23) is a key regulator of urine phosphate excretion. The aim of the study was to investigate the perioperative (intraoperative and postoperative) changes of plasma intact and C-terminal FGF23 (iFGF23, cFGF23) concentrations in patients with primary hyperparathyroidism (pHPT) submitted to surgery. Materials and methods: Study involved 38 adult patients with pHPT caused by adenoma. PTH levels were investigated intraoperatively (just before the incision and 10 minutes after adenoma excision). cFGF23, iFGF23, phosphate, eGFR and P1NP were measured intraoperatively and postoperatively (next day after the surgery). Results: PTH levels decreased intraoperatively (13.10 vs. 4.17 pmol/L, P<0.0001). FGF23 levels measured intraoperatively were at the upper level of reference interval. cFGF23 decreased postoperatively compared with values measured just before the incision (cFGF23: 89.17 vs. 22.23 RU/mL, P<0.0001). iFGF23 decreased as well, but postoperative values were low. Postoperative inorganic phosphate values increased (1.03 mmol/L vs. 0.8 mmol/L, P=0.0025). We proved significant negative correlation of perioperative FGF23 with inorganic phosphate (cFGF23: Spearman r=-0.253,P=0.0065; iFGF23: Spearman r =-0.245, P=0.0085). We also found FGF23 values just before incision correlated with eGFR (cystatin C) (cFGF23: Spearman r=-0.499, P=0.0014; iFGF23: Spearman r=-0.413, P=0.01). Conclusion: Intraoperative iFGF23 and cFGF23 did not change despite PTH decreased significantly. cFGF23 and iFGF23 significantly decreased one day after parathyroidectomy and are associated with increase of inorganic phosphate in pHPT patients. cFGF23 and iFGF23 just before incision correlated with eGFR (cystatin C). The similar results found in both iFGF23 and cFGF23 suggest each could substitute the other.

Normocalcemic primary hyperparathyroidism is an early stage of primary hyperparathyroidism according to fibroblast growth factor 23 level

“…However, similarly to Fořtová M et al. ( 22 ), we did not find any significant difference in bone markers levels or correlation between bone markers and FGF23 levels in the 3 study groups.…”

“…Several studies have failed to demonstrate significantly higher FGF23 levels in PHPT patients with normal renal function than in healthy controls as well as any change in FGF23 concentration after parathyroidectomy ( 12 , 16 – 18 ). In contrast, other studies showed that increased FGF23 levels observed in PHPT significantly decreased after successful parathyroidectomy ( 19 – 22 ). Furthermore, to our knowledge, FGF23 levels have never been previously evaluated in the increasingly recognized NPHPT phenotype.…”

“…In the present study, we found that in patients with NPHPT the FGF23 levels are significantly higher than in the controls, albeit to a lesser extent than in patients with HPHPT. In both groups of patients with PHPT, there was a significant positive correlation (more pronounced in the HPHPT group) between PTH and FGF23 levels, as shown in most ( 18 – 20 ), but not in all studies ( 22 ). Yamashita H et al.…”