title: Risk factors for death from Influenza A(H1N1)pdm09, State of São Paulo, Brazil, 2009.
abstract: This case-control study aimed to assess the risk factors for death from influenza A(H1N1)pdm09 in patients with laboratory confirmation, who had severe acute respiratory illness-SARI and were hospitalized between June 28th and August 29th 2009, in the metropolitan regions of São Paulo and Campinas, Brazil. Medical charts of all the 193 patients who died (cases) and the 386 randomly selected patients who recovered (controls) were investigated in 177 hospitals. Household interviews were conducted with those who had survived and the closest relative of those who had died. 73.6% of cases and 38.1% of controls were at risk of developing influenza-related complications. The 18-to-59-year age group (OR = 2.31, 95%CI: 1.31-4.10 (reference up to 18 years of age)), presence of risk conditions for severity of influenza (OR = 1.99, 95%CI: 1.11-3.57, if one or OR = 6.05, 95%CI: 2.76-13.28, if more than one), obesity (OR = 2.73, 95%CI: 1.28-5.83), immunosuppression (OR = 3.43, 95%CI: 1.28-9.19), and search for previous care associated with the hospitalization (OR = 3.35, 95%CI: 1.75-6.40) were risk factors for death. Antiviral treatment performed within 72 hours of the onset of symptoms (OR = 0.17, 95%CI: 0.08-0.37, if within 48hours, and OR = 0.30, 95%CI: 0.11-0.81, if between 48 and 72 hours) was protective against death. The identification of high-risk patients and early treatment are important factors for reducing morbi-mortality from influenza.
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil; Department of Epidemiology, School of Public Health, University of São Paulo, São Paulo, Brazil.
authors.forename: Ana Freitas
authors.initials: AF
authors.lastname: Ribeiro
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil.
authors.forename: Alessandra Cristina Guedes
authors.initials: AC
authors.lastname: Pellini
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil.
authors.forename: Beatriz Yuko
authors.initials: BY
authors.lastname: Kitagawa
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil.
authors.forename: Daniel
authors.initials: D
authors.lastname: Marques
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil.
authors.forename: Geraldine
authors.initials: G
authors.lastname: Madalosso
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil.
authors.forename: Gerrita
authors.initials: G
authors.lastname: de Cassia Nogueira Figueira
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil.
authors.forename: João
authors.initials: J
authors.lastname: Fred
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil.
authors.forename: Ricardo Kerti Mangabeira
authors.initials: RK
authors.lastname: Albernaz
authors.affiliation: Epidemiological Surveillance Center, Disease Control Coordination, State of São Paulo Department of Health, São Paulo, Brazil.
authors.forename: Telma Regina Marques Pinto
authors.initials: TR
authors.lastname: Carvalhanas
authors.affiliation: Department of Epidemiology, School of Public Health, University of São Paulo, São Paulo, Brazil.
authors.forename: Dirce Maria Trevisan
authors.initials: DM
authors.lastname: Zanetta
mesh_terms: D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D003643:Death; D005260:Female; D006760:Hospitalization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D055815:Young Adult
chemical_list: D000998:Antiviral Agents