IRCT2014061218069N1 IRCT 2014-10-06 Vice Chancellor for Research, Tehran University of Medical Sciences Effect of high dose vitamin D on blood glucose in critically ill patients Comparing effect of high dose vitamin D and placebo on insulin resistance in critically ill patients 2014-03-30 anticipated 50 Complete https://irct.ir/trial/16493 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Other design features: Included patients will be assigned to the intervention (Vit D) or placebo group based on the block randomization method. Vitamin D and its placebo will be prepared by the pharmaceutical company with same packaging and drug formulation properties. The researchers, ICU physicians and patients are blinded and drug will be distributed by the hospital pharmacy department. 3 Hyperglycemia. Intervention 1: Single IM injection of 600000 IU vitamin D3 in intervention group (Two 300000 IU vitamin D3 ampules , each one contains 1 ml of drug). Intervention 2: IM injection of 2 placebo ampules (each one contains 1 ml Placebo).