Introduction: Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone with a significant role in chronic kidney disease (CKD). Serum FGF23 was compared with estimated glomerular filtration rate (eGFR) among CKD patients, renal transplant recipients, and subjects with normal renal function. Methods: A cross-sectional observational study was done in 120 subjects divided into 4 groups of 30 each. (1) eGFR 60 mL/min/1.73 m 2 . FGF23 level was compared with eGFR. Data analysis was done using a Statistical Package for Social Sciences (SPSS) Version 25.0 (Chicago, Illinois, USA SPSS Inc.). P <0.05 was taken as statistically significant. Results: Mean FGF23 was 6027.59 RU/mL, 426.42 RU/mL, 185.23 RU/mL, and 102.95 RU/mL in Groups 1, 2, 3, and 4, respectively. FGF23 and eGFR showed a negative correlation coefficient of −0.930, with P < 0.001. Mean intact parathyroid hormone (iPTH) was 500.64 pg/mL, 140.39 pg/mL, 123.18 pg/mL, and 45.17 pg/mL in Groups 1, 2, 3, and 4, respectively. FGF23 and iPTH showed a positive correlation coefficient of 0.781 and P < 0.001. FGF23 levels were also compared with serum phosphorus, calcium, and 25OH-Vitamin D. FGF23 levels increased with an increase in phosphorus. High FGF23 was associated with low Vitamin D. Conclusion: There is a negative correlation between GFR and serum FGF23. Rise in serum FGF23 occurs in CKD even before a rise in serum PTH or phosphate. Even in postrenal transplant patients, the level of FGF23 was inversely related to GFR. Monitoring serum FGF23 can detect CKD-related mineral bone disorder early.
Rengaswamy et al. (Tue,) studied this question.