title: Pandemic and post-pandemic influenza A (H1N1) seasons in a tertiary care university hospital-high rate of complications compared to previous influenza seasons.
abstract: BACKGROUND
  The aim was to study the characteristics and case severity of patients hospitalized for influenza with a pandemic strain at a German tertiary care university hospital in 2009/10 and 2010/11 and to compare them to two previous influenza seasons.
  
  
  METHODS
  An observational study of all patients hospitalized for laboratory-confirmed influenza during the last four influenza seasons at Regensburg University Hospital was undertaken.
  
  
  RESULTS
  During the last four seasons, a rising number of patients were admitted due to influenza (4 in 2007/8, 16 in 2008/9, 27 in 2009/10, and 55 in 2010/11). Patients seen in the last two seasons were younger (median age 63 years in 2007/8, 52 years in 2008/9, 42 years in 2009/10, and 48 years in 2010/11) (p = 0.046) and presented with a lower rate of major comorbidities (75 % in 2007/8, 62.5 % in 2008/9, 37 % in 2009/10, and 47.3 % in 2010/11). The pandemic and post-pandemic seasons were characterized by a high rate of seriously ill patients with longer hospitalizations (11 days in 2007/8, 7 days in 2008/9, 22 days in 2009/10 and 2010/11) (p = 0.004) and higher rates of intensive care unit (ICU) admission (25 % in 2007/8, 18.8 % in 2008/9, 66.7 % in 2009/10, and 52.7 % in 2010/11) (p = 0.003) and mechanical ventilation (25 % in 2007/8, 6.3 % in 2008/9, 63 % in 2009/10, and 49.1 % in 2010/11) (p < 0.001). Extracorporeal membrane oxygenation (ECMO) was necessary in 33.3 % of patients in 2009/10 and 25.5 % in 2010/11. We had six fatalities in both pandemic and post-pandemic seasons.
  
  
  CONCLUSIONS
  Compared to seasonal influenza, we observed even more so in the post-pandemic than the pandemic season a higher number of younger patients, with less serious comorbidities often showing a very severe course.
authors.affiliation: Department of Internal Medicine I, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany. stilla.bauernfeind@klinik.uni-regensburg.de
authors.forename: S
authors.initials: S
authors.lastname: Bauernfeind
authors.forename: T
authors.initials: T
authors.lastname: Bruennler
authors.forename: B
authors.initials: B
authors.lastname: Ehrenstein
authors.forename: J
authors.initials: J
authors.lastname: Langgartner
authors.forename: J J
authors.initials: JJ
authors.lastname: Wenzel
authors.forename: S
authors.initials: S
authors.lastname: Werner
authors.forename: M
authors.initials: M
authors.lastname: Lubnow
authors.forename: T
authors.initials: T
authors.lastname: Mueller
authors.forename: B
authors.initials: B
authors.lastname: Floerchinger
authors.forename: B
authors.initials: B
authors.lastname: Salzberger
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D005260:Female; D005858:Germany / Q000453:epidemiology; D006785:Hospitals, University; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D058873:Pandemics; D010343:Patient Admission; D012189:Retrospective Studies; D012621:Seasons; D062606:Tertiary Care Centers