Abstract
BACKGROUND: This study explored the possible role of FGF23 in pediatric hypercalciuria. METHODS: Plasma FGF23 was measured in 29 controls and 58 children and adolescents with hypercalciuria: 24 before treatment (Pre-Treated) and 34 after 6 months of treatment (Treated). Hypercalciuric patients also measured serum PTH hormone, 25(OH)vitD, phosphate, calcium, creatinine, and 24 h urine calcium, phosphate, and creatinine. RESULTS: There were no differences in age, gender, ethnicity, or body mass index either between controls and patients, or between Pre-Treated and Treated patients. Median plasma FGF23 in controls was 72 compared with all patients, 58 RU/mL (p = 0.0019). However, whereas FGF23 in Pre-Treated patients, 73 RU/mL, was not different from controls, in Treated patients it was 50 RU/mL, significantly lower than in both controls (p < 0.0001) and Pre-Treated patients (p = 0.02). In all patients, there was a correlation between FGF23 and urinary calcium (r = 0.325; p = 0.0014). Treated patients had significantly lower urinary calcium (p < 0.0001), higher TP/GFR (p < 0.001), and higher serum phosphate (p = 0.007) versus Pre-Treated patients. CONCLUSIONS: Pharmacological treatment of hypercalciuric patients resulted in significantly lower urinary calcium excretion, lower serum FGF23, and elevated TP/GFR and serum phosphate concentration, without significant changes in PTH. Further studies are indicated. This trial is registered with Clinical Registration Number RBR 8W27X5.