title: 2009 H1N1: risk factors for hospitalization in a matched case-control study.
abstract: In order to compare sociodemographical data and preexisting risk medical conditions in patients requiring hospital admission for 2009 pandemic influenza A (H1N1) virus infection and those managed on an outpatient basis, a prospective observational, matched case-control study in 36 hospitals of the Spanish National Health Service was conducted from July 2009 to February 2010. Cases were patients aged 6 months to 18 years hospitalized for influenza syndrome, in whom 2009 influenza A (H1N1) virus infection was confirmed using real-time reverse-transcription polymerase chain reaction. Controls were patients aged 6 months to 18 years with confirmed 2009 influenza A (H1N1) infection managed on an outpatient basis. There were 195 cases and 184 controls. In a multivariate model, hospitalization was more frequent in children aged <2 years (odds ratio (OR), 13.8; 95% confidence interval (CI), 1.7-106.4), those with neurological and/or neuromuscular diseases (OR, 3.0; 95% CI, 1.1-8.2), and those whose parents had less than a secondary educational level (OR, 2.7; 95% CI, 1.4-5.2). Children aged <2 years, children with neurological diseases, and children from families with a lower educational status had a higher risk of hospitalization due to influenza A (H1N1) 2009 infection.
authors.affiliation: Paediatrics Department, Hospital Sant Joan de Déu, University of Barcelona, P. St. Joan de Deu, 2, 08950 Esplugues de Llobregat, Barcelona, Spain.
authors.forename: Cristian
authors.initials: C
authors.lastname: Launes
authors.forename: Juan-José
authors.initials: JJ
authors.lastname: García-García
authors.forename: Aina
authors.initials: A
authors.lastname: Martínez-Planas
authors.forename: Fernando
authors.initials: F
authors.lastname: Moraga
authors.forename: Itziar
authors.initials: I
authors.lastname: Astigarraga
authors.forename: Javier
authors.initials: J
authors.lastname: Arístegui
authors.forename: Javier
authors.initials: J
authors.lastname: Korta
authors.forename: Concepción
authors.initials: C
authors.lastname: Salado
authors.forename: José M
authors.initials: JM
authors.lastname: Quintana
authors.forename: Núria
authors.initials: N
authors.lastname: Soldevila
authors.forename: Angela
authors.initials: A
authors.lastname: Domínguez
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000553:Ambulatory Care / Q000706:statistics & numerical data; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification; D007251:Influenza, Human / Q000150:complications / Q000175:diagnosis / Q000628:therapy*; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D012959:Socioeconomic Factors; D013030:Spain