Serum 25-hydroxyvitamin D level is negatively associated with serum phosphorus level among stage 3a-5 chronic kidney disease patients.

Citation:
Fayed, A., M. M. El Nokeety, A. A. Heikal, K. Marzouk, H. Hammad, D. O. Abdulazim, M. M. Salem, and U. A. Sharaf El Din, "Serum 25-hydroxyvitamin D level is negatively associated with serum phosphorus level among stage 3a-5 chronic kidney disease patients.", Nefrologia : publicacion oficial de la Sociedad Espanola Nefrologia, 2018 May 26.

Abstract:

BACKGROUND: Serum 25-hydroxyvitamin D (25(OH)D) negatively correlates with serum phosphorus level of stage 3a-5 chronic kidney disease (CKD) patients. So far, no explanation has been provided for this negative association.

OBJECTIVE: To confirm this negative association and determine if this relationship is mediated through other known co-morbid factors.

CASES AND METHODS: One hundred (57 male and 43 female) pre-dialysis stage 3a-5 CKD patients were selected. Estimated glomerular filtration rate (eGFR), serum calcium (Ca), phosphorus (P), 25(OH)D, parathyroid hormone (PTH), and intact fibroblast growth factor-23 (FGF23) were assessed. A correlation analysis between serum 25(OH)D and the different parameters studied was performed. Multivariate linear regression analysis was carried out to determine predictors of 25(OH)D.

RESULTS: The negative association between serum 25(OH)D and serum P was confirmed in univariate and multivariate correlation analysis. On the other hand, we failed to detect a significant association between 25(OH)D and serum FGF23. Serum P is the most important independent predictor of 25(OH)D in these patients (partial R=0.15, p<0.0001).

CONCLUSION: Serum P is likely to have a direct negative impact on serum 25(OH)D. Further studies are needed to determine the underlying mechanism.