title: Association between vitamin D deficiency and mortality in critically ill adult patients: a meta-analysis of cohort studies.
abstract: BACKGROUND
  Vitamin D deficiency is common in critically ill patients, and was reported to be associated with adverse outcomes. However, the effect of vitamin D deficiency on mortality in critically ill patients remains unclear.
  
  
  METHODS
  We searched PubMed and EMBASE from the inception to July 2014 for cohort studies to assess the effect of vitamin D deficiency on the incidence of mortality in critically ill patients. Mortality-specific odds ratio (OR) with 95% confidence interval (CI) were pooled with a random- or fixed-effect models when appropriate.
  
  
  RESULTS
  Seven cohort studies with a total of 4,204 participants including 1,679 cases of vitamin D deficiency were included in this meta-analysis. Vitamin D deficiency was significantly associated with an increased hospital mortality (OR 1.76; 95% CI, 1.38 to 2.24; P < 0.001), with very low heterogeneity (I (2) = 2.3%; P = 0.402). The finding of increased hospital mortality in critically ill adult patients was consistently found in every stratum of our subgroup analyses.
  
  
  CONCLUSIONS
  This meta-analysis suggests that vitamin D deficiency is associated with increased incidence of hospital mortality in critically ill adult patients.
authors.affiliation: Department of Integrated Intensive Care Unit, the First Affiliated Hospital, Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450052, China. 1650394713@qq.com.
authors.forename: Yan-Peng
authors.initials: YP
authors.lastname: Zhang
authors.affiliation: Department of Integrated Intensive Care Unit, the First Affiliated Hospital, Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450052, China. wanyoudong130@163.com.
authors.forename: You-Dong
authors.initials: YD
authors.lastname: Wan
authors.affiliation: Department of Integrated Intensive Care Unit, the First Affiliated Hospital, Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450052, China. suntongwen@163.com.
authors.forename: Tong-Wen
authors.initials: TW
authors.lastname: Sun
authors.affiliation: Pharmaceutical Department, the First Affiliated Hospital, Zhengzhou University, 1 Jianshe East Road, Zhengzhou, 450052, China. 1017361289@qq.com.
authors.forename: Quan-Cheng
authors.initials: QC
authors.lastname: Kan
authors.affiliation: School of Biomedical Science, Charles Sturt University, Wagga Wagga, NSW, 2650, Australia. LWang@csu.edu.au.
authors.forename: Le-Xin
authors.initials: LX
authors.lastname: Wang
mesh_terms: D015331:Cohort Studies; D016638:Critical Illness / Q000401:mortality*; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000175:diagnosis / Q000401:mortality*
chemical_list: D014807:Vitamin D