Role of Fibroblast Growth Factor-23 as an Early Marker of Metabolic Bone Disease of Prematurity

Purpose: Metabolic bone disease of prematurity (MBDP) remains a significant cause of morbidity in extremely premature newborns. In high-risk patients, suspected diagnosis and subsequent treatment modifications, with limitations in terms of sensitivity and specificity, rely on low phosphorus levels and/or high levels of alkaline phosphatase (ALP). We investigatedthe potential of fibroblast growth factor-23 (FGF23) as an early marker for MBDP when measured at 3-4 weeks of life in at-risk patients. Methods: : This single-center prospective observational noninterventional study includedpreterm newborns of both sexes, with a gestational age of less than 32 weeks and/or a birth weight of less than 1500 grams. In the standard biochemical screening for MBDP performed between 3 and 4 weeks of life within a nutritional profile, the determination of FGF23 was included along with other clinical and metabolic studies. Results: : In astudy involving 25 at-risk premature newborns, 20% (n=5) were diagnosed with MBDP. Three of these patients (60%) were identified as high-risk based on biochemical evaluation at 3-4 weeks of age, while the other two patients (40%) were diagnosed in subsequent weeks. However, in all 5 patients, measurement of FGF23 levels would allow for early identification and optimization of treatment before other markers become altered. Low levels of FGF23 at 3-4 weeks, even with normal phosphorus and ALP levels, indicatethe need for modifications in nutritional supplementation. Conclusions: : MBDP remains a significant concern in extremely premature newborns. Current diagnostic techniques are limited, necessitating reliance on biochemical markers. Early detection of low FGF23 levels allows for timely treatment interventions, potentially preventing demineralization.