P0892PROFILE OF FIBROBLAST GROWTH FACTOR 23 IN CHRONIC KIDNEY DISEASE IN INDIAN POPULATION
Authors: MAHAJAN SAMEER , ANNIGERI RAJEEV 
Published: June 2020

Abstract

Background
Chronic kidney disease (CKD) is a complex disease. Recent discovery that fibroblast growth factor 23 (FGF23) play a major role in development of CKD related bone mineral disorder (BMD) indicated a paradigm shift in our understanding of CKD–BMD. Recent research indicates that higher levels of FGF23 are associated with rapid progression of CKD and higher mortality in CKD patients. It is found that FGF23 level in blood is elevated significantly early in the course of CKD, even before a rise in parathyroid hormone (PTH) level which could contribute directly to tissue injury in heart, blood vessels and kidneys, apart from just being a marker of adverse outcome, and this needs further research.
The dietary habits, especially phosphate intake is likely to be different in Indian CKD population compared to western CKD population.

Aims and objectives

Method
This is an observational study on 75 consecutive patients visiting Apollo hospital nephrology OPD in Chennai, India from June 2015 to Nov 2015. FGF23 level were determined simultaneously with serum creatinine, albumin, Vitamin D level, serum calcium, phosphate and serum PTH level done on enrolment. Serum samples when not immediately processed, were stored at -20oC.

Results
The age of the patient population varied from 19 to 80 years, mean 53.33 yrs with a SD of 15.49. 57(76%) were males and 18(24%) females. In our study, 46.7%patients belonged to CKD stage 4 while CKD stage 3 and 5 had 25.3% and 28% among the study population respectively.
The mean FGF23 level in study population was 154.82pg/ml (Normal range 11-48.6 pg/ml). Though the FGF23 values in stage 5 CKD were higher than those in stage 3 and 4 CKD, the difference was not statistically significant (p=0.74). In our study, 63 patients (84%) had high FGF23 level and 56(74.7%) patients were already on phosphate binding drugs and PTH suppressing drugs like vit D or cinacalcet for at least 2 months. 48(85.7%) patients of those on medications and 15 (79%) of those not on medications had high FGF23 level (P value -0.48, Yates P value-0.739).
In our study, PTH had an inverse correlation with eGFR and the association was statistically significant (P value 0.001). Serum Phosphorus level had an inverse correlation with eGFR and the association was statistically significant (P value 0.0001). Correlation of FGF23 values with eGFR was negative which was expected as the FGF23 levels increased with decreasing eGFR, but the association was not statistically significant. Similar results were obtained when FGF23 values were studied for association with serum calcium levels where the P value was 0.359 which was not statistically significant. Similarly, vit D levels had a negative association with P value of 0.077 and PTH levels had a positive association with P value of 0.987 (No statistical significance). Similarly, FGF23 levels and phosphate levels had a positive association without statistical significance(p= 0.224).

Conclusion
In conclusion, our data indicate that the rise of serum FGF23 levels in progressive Indian CKD patients is a common finding in CKD stage 3 and beyond.