Risk factors for death from Influenza A(H1N1)pdm09, State of São Paulo, Brazil, 2009

• Published in: PloS one Vol. 10; no. 3; p. e0118772
• Main Authors: Ribeiro, Ana Freitas, Pellini, Alessandra Cristina Guedes, Kitagawa, Beatriz Yuko, Marques, Daniel, Madalosso, Geraldine, de Cassia Nogueira Figueira, Gerrita, Fred, João, Albernaz, Ricardo Kerti Mangabeira, Carvalhanas, Telma Regina Marques Pinto, Zanetta, Dirce Maria Trevisan
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 16-03-2015; Public Library of Science (PLoS)
• Subjects: Adolescent; Adult; Antiviral Agents - therapeutic use; Brazil - epidemiology; Case-Control Studies; Complications; Death; Epidemiology; Fatalities; Female; Health risks; Hospitalization; Humans; Immunosuppression; Influenza; Influenza A; Influenza A Virus, H1N1 Subtype - isolation & purification; Influenza, Human - diagnosis; Influenza, Human - drug therapy; Influenza, Human - epidemiology; Influenza, Human - virology; Male; Metropolitan areas; Middle Aged; Mortality; Obesity; Pandemics; Patients; Prognosis; Respiratory diseases; Risk analysis; Risk Factors; Risk groups; Risk management; Young Adult; Brazil; Mexico; Argentina; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0118772

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.