Effect of cholecalciferol recommended daily allowances on vitamin D status and fibroblast growth factor-23: an observational study in acute burn patients.

OBJECTIVE: Burn patients are at risk of hypovitaminosis D. Optimal vitamin D (VD) intakes are not defined in burn nutrition guidelines and studies mostly focused on ergocalciferol (VD2) supplementation in burn children. Aim of our study was to describe adult burns VD status, to measure effects of our cholecalciferol (VD3) supplementation on VD metabolism during acute burn care, and to assess correlation between FGF23 and C-reactive protein (CRP). DESIGN: Cohort study. METHODS: From March 2012 to January 2013, patients >18 years, admitted within 24 h after injury with burn surface area (BSA) ≥10% were included. Patients daily received VD3 from oral or enteral nutrition (400-600 IU) and from oral or intravenous multivitamin complex (200-220 IU). Serum levels of 25(OH)-D, 1-25(OH)2-D, 3rd generation PTH, C-terminal FGF23, total calcium, phosphate, albumin and CRP were measured at admission (D0) and every week during 4 weeks of follow-up. Data are expressed as percentage or median (min-max). Paired data were compared using Wilcoxon test. Correlation between CRP and FGF23 was assessed using nonparametric Spearman test. A p value <0.05 was considered to be statistically significant. RESULTS: We initially included 24 patients. Median age and BSA were, respectively, 46 [19-86] years and 15 [10-85]%. At D0, 75% presented a VD insufficiency (25(OH)-D 21-29 ng/ml) and 17% presented a deficiency (25(OH)-D ≤20 ng/ml). We followed 12 patients until day 28: 25(OH)-D was unchanged while 1-25(OH)2-D and FGF23 decreased without reaching significance. We observed a significant positive correlation between FGF23 and CRP (r=0.59, 95% CI: 0.22-0.82, p=0.0032). CONCLUSIONS: Most of our adult burns presented hypovitaminosis D regardless of age. Nutrition supplemented with low dose of VD3 (intakes reaching recommended daily allowances) was insufficient to correct 25(OH)-D level. Moreover, an interesting correlation between CRP and FGF23 was found.