The study, published in JAMA, investigated whether the administration of high-dose vitamin D3 has a benefit for critically ill patients who are deficient, after previous research suggested a high prevalence of critically ill patients in an intensive care unit (ICU) have low vitamin D levels.
Indeed, many previous studies have suggested that a low vitamin D status is a significant factor associated with disease severity, mortality, or a shorter survival time in the ICU - and that increasing vitamin D may help to counteract this.
However, data from the new randomised trial, led by Karin Amrein from the Medical University of Graz, Austria, suggests that administration of high-dose vitamin D does not improve outcomes in a way that many had predicted it could.
"Among patients with vitamin D deficiency who are critically ill, administration of high-dose vitamin D3 compared with placebo did not improve hospital length of stay, hospital mortality, or 6-month mortality,” wrote the team.
Amrein and colleagues randomly assigned 492 adult ICU patients with vitamin D deficiency to receive either high-dose vitamin D3 (n = 249) or a placebo (n = 243).
The patients received either vitamin D3 or the placebo either orally or via nasogastric tube at an initial level of 540,000 International Units (IU) of vitamin D3, followed by monthly maintenance doses of 90,000 IU for 5 months. The primary outcome was hospital length of stay, while secondary outcomes included, length of ICU stay, hospital mortality, and six-month mortality.
For the primary study outcome, length of hospital stay, the vitamin D3 group was not significantly different from the placebo group: 20.1 days vs 19.3 days. There was also no significant difference for length of ICU stay: 9.6 days for the vitamin D3 group vs 10.7 days for the placebo group, said the researchers.
Hospital mortality and six-month mortality were also not significantly different with hospital mortality at 28.3% for vitamin D3 vs 35.3% for placebo and six-month mortality found to be 35.0% for vitamin D3 vs 42.9% for placebo.
Amrein and her team noted that lower hospital mortality was observed in a subgroup of patients with severe vitamin D deficiency, but added that this finding “should be considered hypothesis generating and requires further study.”
“Despite adequate power, the results of our primary end point (length of hospital stay) were negative for both the intention-to-treat population as well as the severe vitamin D deficiency subgroup,” concluded the team. “In the overall cohort, hospital and 6-month mortality rates were numerically lower in the vitamin D3 group, but these differences were not significant.”
Published online ahead of print, doi: 10.1001/jama.2014.13204
“Effect of High-Dose Vitamin D3 on Hospital Length of Stay in Critically Ill Patients With Vitamin D Deficiency. The VITdAL-ICU Randomized Clinical Trial”
Authors: Karin Amrein, Christian Schnedl, et al