Serum FGF-23 levels in predialysis chronic kidney disease are not associated with 25-OH D vitamin levels

Abstract

Aim: Vitamin D has been found to have effects on the neurological, immunological and endocrine systems in addition to its effects on bone mineral metabolism. Similar to the population in general, in patients with chronic kidney disease (CKD), vitamin D deficiency has been shown to be associated with progression of renal disease, increased cardiovascular mortality and morbidity. In this study, we aimed to determine the factors affecting the vitamin D level in our CKD patients. Method: One hundred and twenty patients with CKD but not on dialysis who were admitted to our nephrology clinic were included in the study. Results: Sixty-eight patients (56.7%) had vitamin D deficiency, 47 (39.2%) had vitamin D insufficiency. Sixty-eight patients had vitamin D levels of <15 pg/ml and> 56 pg/ml in 56 patients. Vitamin D levels in patients with, and without DM were 12.9±6.6 pg/ ml and 16±8.1 pg/ml, respectively with a statistically significant intergroup difference (p<0.05). In univariate correlation analysis, vitamin D was negatively correlated with phosphorus (rs =-0.30, p<0.001), PTH (rs =-0.34, p<0.001), proteinuria (rs =-0.22) and DM (rs=-0.19, p<0.05), while positively correlated with hemoglobin (rs=0.27, p< 0.001). However we did not find any correlation between 25-OH-D and FGF 23 and (rs=-0.122, p=0.183), eGFR (p=0.183, rs=0.135). In multivariate linear regression analysis, only PTH (beta =-0.24, p<0.01) and glomerular filtration rate (beta =-0.215, p<0.05) were found to have a negative effect on vitamin D. Conclusion: In recent years, in addition to classical mineral metabolism of vitamin D, its pleotropic role and clinical consequences in predialysis CKD patients have been better understood. For this reason it is of great importance to know the factors affecting the vitamin D levels in this patient group and to consider them in the treatment of the patients. © 2018, Logos Medical Publishing. All rights reserved.