Epidemiology, Clinical Features, and Prognosis of Elderly Adults with Severe Forms of Influenza A (H1N1)

Objectives 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. Design Prospective, observational, multicenter study to determine prognostic factors in individuals infected with influenza A (H1N1) admitted to the ICU. Setting One hundred forty‐eight Spanish ICUs. Participants Individuals with influenza A (H1N1) confirmed using real‐time polymerase chain reaction from April 2009 to July 2011. Measurements 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