title: Epidemiology of influenza-associated hospitalization in adults, Toronto, 2007/8.
abstract: The purpose of this investigation was to identify when diagnostic testing and empirical antiviral therapy should be considered for adult patients requiring hospitalization during influenza seasons. During the 2007/8 influenza season, six acute care hospitals in the Greater Toronto Area participated in active surveillance for laboratory-confirmed influenza requiring hospitalization. Nasopharyngeal (NP) swabs were obtained from patients presenting with acute respiratory or cardiac illness, or with febrile illness without clear non-respiratory etiology. Predictors of influenza were analyzed by multivariable logistic regression analysis and likelihoods of influenza infection in various patient groups were calculated. Two hundred and eighty of 3,917 patients were found to have influenza. Thirty-five percent of patients with influenza presented with a triage temperature >or=38.0 degrees C, 80% had respiratory symptoms in the emergency department, and 76% were >or=65 years old. Multivariable analysis revealed a triage temperature >or=38.0 degrees C (odds ratio [OR] 3.1; 95% confidence interval [CI] 2.3-4.1), the presence of respiratory symptoms (OR 1.7; 95% CI 1.2-2.4), admission diagnosis of respiratory infection (OR 1.8; 95% CI 1.3-2.4), admission diagnosis of exacerbation of chronic obstructive pulmonary disease (COPD)/asthma or respiratory failure (OR 2.3; 95% CI 1.6-3.4), and admission in peak influenza weeks (OR 4.2; 95% CI 3.1-5.7) as independent predictors of influenza. The likelihood of influenza exceeded 15% in patients with respiratory infection or exacerbation of COPD/asthma if the triage temperature was >or=38.0 degrees C or if they were admitted in the peak weeks during the influenza season. During influenza season, diagnostic testing and empiric antiviral therapy should be considered in patients requiring hospitalization if respiratory infection or exacerbation of COPD/asthma are suspected and if either the triage temperature is >or=38.0 degrees C or admission is during the weeks of peak influenza activity.
authors.affiliation: Department of Microbiology, Room 210, Mount Sinai Hospital, 600 University Ave., Toronto, Ontario M5G 1X5, Canada.
authors.forename: S P
authors.initials: SP
authors.lastname: Kuster
authors.forename: S
authors.initials: S
authors.lastname: Drews
authors.forename: K
authors.initials: K
authors.lastname: Green
authors.forename: J
authors.initials: J
authors.lastname: Blair
authors.forename: I
authors.initials: I
authors.lastname: Davis
authors.forename: J
authors.initials: J
authors.lastname: Downey
authors.forename: R
authors.initials: R
authors.lastname: Fowler
authors.forename: K
authors.initials: K
authors.lastname: Katz
authors.forename: S
authors.initials: S
authors.lastname: Lapinsky
authors.forename: D
authors.initials: D
authors.lastname: McRitchie
authors.forename: J
authors.initials: J
authors.lastname: Pataki
authors.forename: J
authors.initials: J
authors.lastname: Powis
authors.forename: D
authors.initials: D
authors.lastname: Rose
authors.forename: A
authors.initials: A
authors.lastname: Sarabia
authors.forename: C
authors.initials: C
authors.lastname: Simone
authors.forename: A
authors.initials: A
authors.lastname: Simor
authors.forename: T
authors.initials: T
authors.lastname: Stewart
authors.forename: A
authors.initials: A
authors.lastname: McGeer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009305:Nasopharynx / Q000821:virology; D055815:Young Adult