Vitamin D dosing study in Intensive Care Unit patients

Deficiency of vitamin D has been increasingly recognised as a significant public health problem, even in a sunny country like Australia. We and other groups have found that this deficiency is even more common and pronounced in critically ill patients in the Intensive Care Unit.(ICU) There is now scientific evidence suggesting that vitamin D has widespread roles outside its traditionally recognised role in bone health. Its deficiency has been associated with cardiovascular disease, some cancers, autoimmune and inflammatory diseases, etc. We therefore propose that supplementing vitamin D in critically ill patients while they are in the ICU, particularly those showing signs of an inflammatory response, may improve their outcomes. This needs to be studied in depth within the context of a well-designed, large clinical trial. As a variety of doses are currently used in clinical practice, the appropriate dose that is required, particularly in patients who are critically ill, is not known. The design of such trials can only be achieved by obtaining extensive background information on safety and the effects of supplementation using different doses, which are in common use, to determine which dose to use in further trials of critically ill patients and what effects can be achieved with this. Such studies are not available currently. Fortunately, vitamin D is a medication that can be used safely in a wide range of doses and we plan to use 2 doses within this range. In this study, 50 patients admitted to the ICU who meet certain criteria, suggesting that they have signs of the inflammatory response, will be randomly allocated to receive one of 2 single doses of vitamin D by intramuscular injection. We will collect a small quantity of blood for testing at baseline and on days 1,3,7 and 14 following the dose. We will measure vitamin D and metabolite levels and markers of inflammation in order to study whether target levels can be obtained with these doses and also what effect it has on the inflammatory response. We will monitor closely for any side effects, although these would be extremely unlikely in the doses that we propose to use. We will also collect information from the patients record on routinely collected clinical data and certain outome measures. All information collected and presented will be de-identified and all records will be securely maintained to ensure privacy. This study will provide us with vital information that we require for the next stage of this project, which is the development of a large study in a number of ICUs to explore the effects of vitamin D supplementation on outcome in this patient group. If shown to be beneficial, this could be an intervention that has a widespread global impact, including in low and middle income countries, as vitamin D is a cheap, safe and easily available medication.