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vol.84 issue5Enhanced surveillance of initial cases of pandemic influenza (H1N1) 2009 infection in Spain, April-June 2009Surveillance of influenza Pandemic (H1N1)2009 in Spain author indexsubject indexarticles search
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Revista Española de Salud Pública

Print version ISSN 1135-5727

Abstract

SANTA-OLALLA PERALTA, Patricia  and  SUBCOMITE DE VIGILANCIA EPIDEMIOLOGICA DEL PLAN NACIONAL DE PREPARACION Y RESPUESTA ANTE UNA PANDEMIA DE GRIPE et al. Critically ill patients with 2009 pandemic influenza A (H1N1) infection in Spain: factors associated with death, April 2009-January 2010. Rev. Esp. Salud Publica [online]. 2010, vol.84, n.5, pp. 547-567. ISSN 1135-5727.  http://dx.doi.org/10.1590/S1135-57272010000500008.

Background: It is necessary to analyse the severe cases of pandemic influenza infection in order to identify vulnerable populations and adapt prevention and control policies accordingly. We analysed the clinical and epidemiological characteristics and risk factors associated with death in patients with 2009 pandemic influenza A (H1N1) infection hospitalised in intensive care units (ICUs) in Spain and reported from 24 April 2009 to 31 January 2010. Methods: As part of the national strategy for surveillance of hospitalized cases with pandemic influenza, cased-based clinical and epidemiological information on all cases admitted to an ICU with 2009 pandemic virus (H1N1) infection was collected nationwide. Results: Of 1,231 cases admitted to ICU, 271 died (case fatality ratio, 22%). The median age was 40 years (range: 0-90). A total of 838 (76.3%) patients had an underlying risk condition, being respiratory disease the most frequently reported (34.1%), followed by morbid obesity (18.8%), in adults. Antiviral treatment was given in 93.1% patients and in 25.6% (n = 231) it was initiated within 48 hours of symptoms onset. In a multivariate analysis, cancer (OR 2.71, 95%CI 1.44 to 5.1), immunodeficiency (OR 2.25, 95%CI 1.29 - 3.92) and morbid obesity (OR 1.79, 95%CI 1.13 to 2.85) were significantly associated with death in adults. Conclusions: The characterization of severe pandemic influenza cases has been crucial in identifying as risk factors of complications and death from influenza the presence of cancer and immunodeficiencies and for the first time, morbid obesity in adults.

Keywords : Pandemic; Influenza A Virus; H1N1 Subtype; Spain; Population surveillance; Intensive Care Unit; Obesity; Risk factor; Death; Complications; Neoplasm.

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