title: Serum Vitamin D levels at admission predict the length of intensive care unit stay but not in-hospital mortality of critically ill surgical patients.
abstract: OBJECTIVE
  There is few data regarding the correlation between serum Vitamin D level and unfavorable intensive care unit (ICU) outcome in postsurgical patients. In this study, correlation between serum 25(OH)D level and length of ICU stay and in-hospital mortality has been evaluated in critically ill surgical patients.
  
  
  METHODS
  Serum 25(OH)D has been evaluated in 70 surgical, critically ill patients. Demographic, laboratory, and clinical data of the patients were collected. Correlation between serum 25(OH) D level and duration of ICU stay and hospital mortality was evaluated using two-factor analysis of covariance. Multivariable Cox-regression analysis was used for adjusting the effect of season of blood sampling and type of surgery on the main variables. For all the analyses, P values less than or equal to 0.05 were considered as statistically significant.
  
  
  RESULTS
  Serum 25(OH)D deficiency was identified in 52 (74.3%) of the patients. Patients with serum Vitamin D levels < 30 ng/ml had longer length of ICU stay than those with serum Vitamin D levels ≥ 30 ng/ml (7.8 ± 5.1 vs. 4.05 ± 2.12 days, P = 0.003). Although hospital mortality was more common in Vitamin D deficient patients than sufficient ones (25% in deficient group versus 22.2% in sufficient group), there was no significant difference regarding hospital mortality rate between the groups.
  
  
  CONCLUSIONS
  Statistically significant association was found between low 25(OH)D level and increased length of ICU stay in critically ill surgical patients. It could be explained by favorable effects of Vitamin D on immune system functions, reducing tissue dysfunction, and risk of organ failure and overall complications. However, there was no correlation between serum Vitamin D level and patients' in-hospital mortality. Further, well-designed prospective clinical studies with adequate sample size are needed to evaluate correlation between serum Vitamin D level and mortality in critically ill patients.
authors.affiliation: Department of Clinical Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Nafiseh
authors.initials: N
authors.lastname: Alizadeh
authors.affiliation: Department of Clinical Pharmacy, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Khalili
authors.affiliation: Department of Intensive Care Unit, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Mohammadi
authors.affiliation: Department of Pathology, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Abdollahi
keywords: Critically ill patients; Vitamin D; intensive care unit stay; mortality; surgical