title: Risk of acute lung injury/acute respiratory distress syndrome in critically ill adult patients with pre-existing diabetes: a meta-analysis.
abstract: BACKGROUND
  The impact of pre-existing diabetes on the development of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) in critically ill patients remains unclear. We performed a meta-analysis of cohort studies to evaluate the risk of ALI/ARDS in critically ill patients with and without pre-existing diabetes.
  
  
  METHODS
  We searched PubMed and Embase from the inception to September 2013 for cohort studies assessing the effect of pre-existing diabetes on ALI/ARDS occurrence. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using random- or fixed-effect models when appropriate.
  
  
  RESULTS
  Seven cohort studies with a total of 12,794 participants and 2,937 cases of pre-existing diabetes, and 2,457 cases of ALI/ARDS were included in the meta-analysis. A fixed-effects model meta-analysis showed that pre-existing diabetes was associated with a reduced risk of ALI/ARDS (OR 0.66; 95% CI, 0.55-0.80; p<0.001), with low heterogeneity among the studies (I(2)=18.9%; p=0.286). However, the asymmetric funnel plot and Egger's test (p=0.007) suggested publication bias may exist.
  
  
  CONCLUSIONS
  Our meta-analysis suggests that pre-existing diabetes was associated with a decreased risk of ALI/ARDS in critically ill adult patients. However, the result should be interpreted with caution because of the potential bias and confounding in the included studies.
authors.affiliation: Department of Anaesthesiology, the First Affiliated Hospital, Guangxi Medical University, Nanning, China ; Department of Integrated Intensive Care Unit, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China.
authors.forename: Wan-Jie
authors.initials: WJ
authors.lastname: Gu
authors.affiliation: Department of Integrated Intensive Care Unit, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China.
authors.forename: You-Dong
authors.initials: YD
authors.lastname: Wan
authors.affiliation: The First College of Clinical Medicine, the First Affiliated Hospital, Chongqing Medical University, Chongqing, China.
authors.forename: Hong-Tao
authors.initials: HT
authors.lastname: Tie
authors.affiliation: Pharmaceutical Department, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China.
authors.forename: Quan-Cheng
authors.initials: QC
authors.lastname: Kan
authors.affiliation: Department of Integrated Intensive Care Unit, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, China.
authors.forename: Tong-Wen
authors.initials: TW
authors.lastname: Sun
mesh_terms: D055371:Acute Lung Injury / Q000453:epidemiology* / Q000209:etiology*; D000328:Adult; D015897:Comorbidity; D016638:Critical Illness; D003920:Diabetes Mellitus; D006801:Humans; D016017:Odds Ratio; D017594:Publication Bias; D012128:Respiratory Distress Syndrome / Q000453:epidemiology* / Q000209:etiology*; D012306:Risk