Vitamin D levels in critically ill patients with acute kidney injury: a protocol for a prospective cohort study (VID-AKI)

Abstract

IntroductionAcute kidney injury (AKI) affects more than 50% of critically ill patients. The formation of calcitriol, the active vitamin D metabolite, from the main inactive circulating form, 25-hydroxyvitamin D (25(OH)D), occurs primarily in the proximal renal tubules. This results in a theoretical basis for reduction in levels of calcitriol over the course of an AKI. Vitamin D deficiency is highly prevalent in critically ill adults, and has been associated with increased rates of sepsis, longer hospital stays and increased mortality. The primary objective of this study is to perform serial measurements of 25(OH)D and calcitriol (1,25(OH)2D), as well as parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) levels, in critically ill adult patients with and without AKI, and to determine whether patients with AKI have significantly lower vitamin D metabolite concentrations. The secondary objectives are to describe dynamic changes in vitamin D metabolites, PTH and FGF23 during critical illness; to compare vitamin D metabolite concentrations in patients with AKI with and without renal replacement therapy; and to investigate whether there is an association between vitamin D status and outcomes.Methods and analysis230 general adult intensive care patients will be recruited. The AKI arm will include 115 critically ill patients with AKI Kidney Disease Improving Global Outcome stage II or stage III. The comparison group will include 115 patients who require cardiovascular or respiratory support, but who do not have AKI. Serial measurements of vitamin D metabolites and associated hormones will be taken on prespecified days. Patients will be recruited from two large teaching Trusts in England. Data will be analysed using standard statistical methods.Ethics and disseminationEthical approval was obtained. Upon completion, the study team will submit the study report for publication in a peer-reviewed scientific journal and for conference presentation.Trial registration numberNCT02869919; Pre-results.

Vitamin D in acutely ill patients

“… 47 A study has been designed to access the effect of vitamin D deficiency as well as vitamin D metabolism in adult acute care unit patients with and without acute kidney injury. 48 Very interestingly, and in contrast to the previous findings, 47 high levels of 1,25(OH) 2 D 3 (calcitriol) were found to be related to adverse outcome in critically ill patients with acute kidney injury. 49 In a study performed in Italy in patients admitted to an intensive care unit, low levels of 25(OH)D 3 were observed in patients with sepsis, but no relationship with survival was observed.…”

Micronutrients in critically ill patients with severe acute kidney injury – a prospective study

“…Vitamin D concentrations are also frequently low during critical illness, but less is known about the metabolism of vitamin D and other fat-soluble vitamins in AKI. Druml and colleagues measured plasma concentrations of vitamin A, E, D and K in AKI patients treated with haemodialysis and reported profound deficiencies with the exception of vitamin K. 23 More research is ongoing 24 .…”

Dysregulated Mineral Metabolism in AKI

“…An ongoing prospective cohort study of 230 critically ill patients admitted to ICUs in the United Kingdom is seeking to address this question, as well as the kinetics of 25D and 1,25D levels in critically ill patients with and without AKI. 122 Clinical relevance of decreased 25D and 1,25D in AKI…”