Serum fibroblast growth factor-23 levels predict the future refractory hyperparathyroidism in dialysis patients

Serum fibroblast growth factor-23 levels predict the future refractory hyperparathyroidism in dialysis patients. Secondary hyperparathyroidism is a common complication among long-term dialysis patients. The method of predicting future parathyroid function has not yet been established. Fibroblast growth factor-23 (FGF-23) is a newly found humoral phosphaturic factor. One hundred and three nondiabetic dialysis patients whose plasma intact parathyroid hormone (PTH) levels were below 300 pg/mL were included in the study. Blood samples were stored at -80°C for 2 years. Meanwhile, each physician in charge decided upon the strategy of medical therapy for maintaining intact PTH levels between 150 and 300 pg/mL. Patients were judged 2 years after the sample collection with regard to whether the hyperparathyroidism responded to the medical therapy. The definition of refractory secondary hyperparathyroidism was either (1) retaining intact PTH levels greater than 300 pg/mL 2 years after sample collection, or (2) having received the parathyroid intervention therapy during the observation period. Serum FGF-23 levels were determined with a sandwich enzyme-linked immunosorbent assay system that detects biologically active human FGF-23. Seventeen patients with intact PTH levels greater than 300 pg/mL were judged as having secondary hyperparathyroidism refractory to medical therapy. A stepwise regression analysis revealed that only serum levels of FGF-23 were significantly related to the prognosis of parathyroid function. A receiver-operated characteristic analysis demonstrated that the area under the curves obtained from FGF-23 (7099.9) was significantly greater than that obtained from intact PTH (6306.4, P < .01) and Ca × Pi (5670.3, P