#1230 Comparative analysis of vitamin D status between patients with advanced chronic kidney disease and those on dialysis

Abstract

Abstract Background and Aims Decreased plasma concentration of 1,25-dihydroxy-vitamin D3 or calcitriol, the most active biological form of vitamin D3, in patients with advanced chronic kidney disease (ACKD) and on dialysis, is almost universal. In addition, 25-50% of these patients also have decreased levels of 25-hydroxy-vitamin D3 (calcidiol or calcifediol). The main cause of calcitriol deficiency is decreased hydroxylation in the kidney, both due to intrinsic renal damage and hyperphosphataemia. Calcifediol deficiency is directly related to decreased intake and sun exposure. We already know that this calcifediol deficiency is associated with ACKD, but we do not know if there are differences between ACKD patients and dialysis patients. The aim of this study is to analyse whether there are differences in calcifediol levels between ACKD and dialysis patients. Method An observational, analytical, ambispective, multicentre, analytical study was carried out with the participation of five Centres in Spain, under conditions of routine clinical practice. As study subjects, we included patients with ACKD and on haemodialysis from the University Hospitals of Virgen del Rocío, La Paz and Nuestra Señora de Candelaria, and the dialysis centres: Avericum, Quironsalud Tenerife. We selected demographic variables and also included serum levels of calcifediol, calcium, phosphorus and PTH; treatment with: phosphorus binders, erythropoietin synthesis analogues (ESA), ferrotherapy, calcimimetics, active vitamin D, native vitamin D. Data are organised and analysed with SPSS Statistics v22. In all analyses, the significance level is set for a P value < 0.05. Multivariate logistic regression analysis was also performed. Results A total of 161 patients were included. Both groups were homogeneous in the presence of diabetes, calcium levels and treatment with iron, native vitamin D, active vitamin D and calcimimetics. There were significant differences in sex, age, phosphorus levels, PTH, phosphate binders, ESA treatment. There are no significant differences in calcifediol levels or vitamin D status between the two comparison groups. Conclusion In our study, within a general context of hypovitaminosis D, patients with ACKD have a vitamin D status similar to dialysis patients.