title: Effect of corticosteroid therapy on influenza-related mortality: a systematic review and meta-analysis.
abstract: BACKGROUND
  Most studies have reported that corticosteroid therapy adversely influences influenza-related outcomes.
  
  
  METHODS
  Electronic databases were searched from inception to March 2013 for experimental and observational studies investigating systemic corticosteroid therapy for presumed influenza-associated complications. Meta-analysis of Observational Studies in Epidemiology guidelines were adopted. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using random-effects models, and heterogeneity was assessed using the I(2) statistic. Quality of evidence was assessed using the Grading Assessment, Development, and Evaluation system.
  
  
  RESULTS
  We identified 16 eligible studies (3039 individuals), all of which were observational; 10 (1497 individuals) were included in the meta-analysis of mortality, of which 9 studied patients with 2009 pandemic influenza A virus subtype H1N1. Risk of bias was greatest in the comparability domain of the Newcastle-Ottawa scale, consistent with potential confounding by indication, and data specific to mortality were of low quality. Meta-analysis found an increased odds of mortality (OR, 2.12; 95% CI, 1.36-3.29) associated with corticosteroid therapy. Subgroup analysis of adjusted estimates from 4 studies with very low statistical heterogeneity found a similar association (OR, 2.58; 95% CI, 1.39-4.79).
  
  
  CONCLUSIONS
  No completed clinical trials were identified. Evidence from observational studies, with important limitations, suggests that corticosteroid therapy for presumed influenza-associated complications is associated with increased mortality.
authors.affiliation: Nottingham University Hospitals NHS Trust.
authors.forename: Chamira
authors.initials: C
authors.lastname: Rodrigo
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, United Kingdom.
authors.forename: Jo
authors.initials: J
authors.lastname: Leonardi-Bee
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, United Kingdom.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Nguyen-Van-Tam
authors.affiliation: Nottingham University Hospitals NHS Trust.
authors.forename: Wei Shen
authors.initials: WS
authors.lastname: Lim
mesh_terms: D000305:Adrenal Cortex Hormones / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D007155:Immunologic Factors / Q000009:adverse effects* / Q000627:therapeutic use; D007251:Influenza, Human / Q000150:complications / Q000188:drug therapy / Q000401:mortality*; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones; D007155:Immunologic Factors
keywords: corticosteroid; influenza