title: High-dose intravenous selenium does not improve clinical outcomes in the critically ill: a systematic review and meta-analysis.
abstract: BACKGROUND
  Selenium (Se) is an essential trace element with antioxidant, anti-inflammatory, and immunomodulatory effects. So far, several randomized clinical trials (RCTs) have demonstrated that parenteral Se may improve clinical outcomes in intensive care unit (ICU) patients. Since publication of our previous systematic review and meta-analysis on antioxidants in the ICU, reports of several trials have been published, including the largest RCT on Se therapy. The purpose of the present systematic review was to update our previous data on intravenous (IV) Se in the critically ill.
  
  
  METHODS
  We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials. We included RCTs with parallel groups comparing parenteral Se as single or combined therapy with placebo. Potential trials were evaluated according to specific eligibility criteria, and two reviewers abstracted data from original trials in duplicate independently. Overall mortality was the primary outcome; secondary outcomes were infections, ICU length of stay (LOS), hospital LOS, ventilator days, and new renal dysfunction.
  
  
  RESULTS
  A total of 21 RCTs met our inclusion criteria. When the data from these trials were aggregated, IV Se had no effect on mortality (risk ratio [RR] 0.98, 95 % CI 0.90-1.08, P = 0.72, heterogeneity I2= 0 %). In addition, when the results of ten trials in which researchers reported on infections were statistically aggregated, there was no significant treatment effect of parenteral Se (RR 0.95, 95 % CI 0.88-1.02, P = 0.15, I2= 0 %). There was no positive or negative effect of Se therapy on ICU and hospital LOS, renal function, or ventilator days.
  
  
  CONCLUSIONS
  In critically ill patients, IV Se as monotherapy does not improve clinical outcomes.
authors: Department of Critical Care, Intensive Care Unit, Hospital de Clínicas (University Hospital), Faculty of Medicine, Universidad de la República (UdelaR), Avenida Italia, 14th Floor, Montevideo, 11.600, Uruguay. wmanzanares@adinet.com.uy.
authors: William
authors: W
authors: Manzanares
authors: Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, ON, Canada.
authors: Margot
authors: M
authors: Lemieux
authors: Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors: Gunnar
authors: G
authors: Elke
authors: Centre Hospitalier Universitaire de Sherbrooke, Hospital Fleurimont, Sherbrooke, QC, Canada.
authors: Pascal L
authors: PL
authors: Langlois
authors: Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany.
authors: Frank
authors: F
authors: Bloos
authors: Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, ON, Canada.|Department of Medicine, Queen's University, Kingston, ON, Canada.
authors: Daren K
authors: DK
authors: Heyland
mesh_terms: D000975:Antioxidants / Q000008:administration & dosage*; D016638:Critical Illness / Q000401:mortality* / Q000628:therapy*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007262:Infusions, Intravenous; D009026:Mortality / Q000639:trends; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D012643:Selenium / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D000975:Antioxidants; D012643:Selenium
keywords: Antioxidant micronutrient; Critically ill; Intravenous selenium; Parenteral selenium