Epidemiology, Clinical Features, and Prognosis of Elderly Adults with Severe Forms of Influenza A ( H1 N1).

Objectives To examine epidemiological and clinical data of individuals aged 65 and older with influenza virus A ( H1 N1) 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 ( H1 N1) admitted to the ICU. Setting One hundred forty-eight Spanish ICUs. Participants Individuals with influenza A ( H1 N1) 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 < .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). Conclusion Individuals aged 65 and older with influenza A ( H1 N1) 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. [ABSTRACT FROM AUTHOR]