title: Epidemiology, clinical features, and prognosis of elderly adults with severe forms of influenza A (H1N1.
abstract: OBJECTIVE
  To examine epidemiological and clinical data of individuals aged 65 and older with influenza virus A (H1N1) admitted to the intensive care unit (ICU) and to identify independent predictors of ICU mortality.
  
  
  METHODS
  Prospective, observational, multicenter study to determine prognostic factors in individuals infected with influenza A (H1N1) admitted to the ICU.
  
  
  METHODS
  One hundred forty-eight Spanish ICUs.
  
  
  METHODS
  Individuals with influenza A (H1N1) confirmed using real-time polymerase chain reaction from April 2009 to July 2011.
  
  
  METHODS
  Individuals aged 65 and older were compared with younger individuals. A multivariate analysis was conducted to determine independent predictors of mortality in this population.
  
  
  RESULTS
  One thousand one hundred twenty individuals (129 (11.5%) aged 65) were included. Prevalence of chronic diseases was more common in older individuals. Viral pneumonitis was more frequent in individuals younger than 65 (70.5% vs 54.3%, P < .001). In older individuals, Acute Physiology and Chronic Health Evaluation II score (odds ratio (OR) = 1.11, 95% confidence interval (CI) = 1.11–1.20, P = .002), immunosuppression (OR = 3.66, 95% CI, 1.33–10.03, P = .01) and oseltamivir therapy initiated after 48 hours (OR = 3.32, 95% CI = 1.02–10.8, P = .04) were identified as independent variables associated with mortality. Corticosteroid use was associated with a trend toward greater mortality (OR = 2.39, 95% CI = 0.98–5.91, P = .06).
  
  
  CONCLUSIONS
  Individuals aged 65 and older with influenza A (H1N1) admitted to the ICU have a higher incidence of underlying diseases than younger individuals and differences in clinical presentation. Early oseltamivir therapy is associated with better outcomes in elderly adults.
authors.affiliation: Critical Care and Emergency Department, Hospital Virgen del Rocío, Seville, Spain. jgarnachom@gmail.com
authors.forename: José
authors.initials: J
authors.lastname: Garnacho-Montero
authors.forename: Antonio
authors.initials: A
authors.lastname: Gutiérrez-Pizarraya
authors.forename: Juan A
authors.initials: JA
authors.lastname: Màrquez
authors.forename: Rafael
authors.initials: R
authors.lastname: Zaragoza
authors.forename: Rosa
authors.initials: R
authors.lastname: Granada
authors.forename: Sergio
authors.initials: S
authors.lastname: Ruiz-Santana
authors.forename: Jordi
authors.initials: J
authors.lastname: Rello
authors.forename: Alejandro
authors.initials: A
authors.lastname: Rodríguez
mesh_terms: D017677:Age Distribution; D000368:Aged; D000998:Antiviral Agents / Q000627:therapeutic use*; D016022:Case-Control Studies; D002908:Chronic Disease / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000188:drug therapy* / Q000453:epidemiology / Q000401:mortality*; D007362:Intensive Care Units / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D053139:Oseltamivir / Q000627:therapeutic use*; D011379:Prognosis; D011446:Prospective Studies; D013030:Spain / Q000453:epidemiology; D016019:Survival Analysis
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir