title: Community-acquired pneumonia during the first post-pandemic influenza season: a prospective, multicentre cohort study.
abstract: OBJECTIVE
  To determine the aetiology, clinical features and prognosis of CAP during the first post-pandemic influenza season. We also assessed the factors associated with severe disease and tested the ability of a scoring system for identifying influenza A (H1N1)pdm09-related pneumonia.
  
  
  METHODS
  Prospective cohort study carried out at 10 tertiary hospitals of Spain. All adults hospitalised with CAP from December 01, 2010 to March 31, 2011 were analysed.
  
  
  RESULTS
  A total of 747 adults with CAP required hospitalisation. The aetiology was determined in 315 (42.2%) patients, in whom 154 (21.9%) were due to bacteria, 125 (16.7%) were due to viruses and 36 (4.8%) were mixed (due to viruses and bacteria). The most frequently isolated bacteria were Streptococccus pneumoniae. Among patients with viral pneumonia, the most common organism identified were influenza A (H1N1)pdm09. Independent factors associated with severe disease were impaired consciousness, septic shock, tachypnea, hyponatremia, hypoxemia, influenza B, and influenza A (H1N1)pdm09. The scoring system evaluated did not differentiate reliably between patients with influenza A (H1N1)pdm09-related pneumonia and those with other aetiologies.
  
  
  CONCLUSIONS
  The frequency of bacterial and viral pneumonia during the first post-pandemic influenza season was similar. The main identified virus was influenza A (H1N1)pdm09, which was associated with severe disease. Although certain presenting clinical features may allow recognition of influenza A (H1N1)pdm09-related pneumonia, it is difficult to express them in a reliable scoring system.
authors.affiliation: Hospital Universitari de Bellvitge - IDIBELL, University of Barcelona, Feixa Llarga s/n, 08907 Barcelona, Spain. dfviasusp@gmail.com
authors.forename: Diego
authors.initials: D
authors.lastname: Viasus
authors.forename: Carmen
authors.initials: C
authors.lastname: Marinescu
authors.forename: Aroa
authors.initials: A
authors.lastname: Villoslada
authors.forename: Elisa
authors.initials: E
authors.lastname: Cordero
authors.forename: Juan
authors.initials: J
authors.lastname: Gálvez-Acebal
authors.forename: María C
authors.initials: MC
authors.lastname: Fariñas
authors.forename: Irene
authors.initials: I
authors.lastname: Gracia-Ahufinger
authors.forename: Anabel
authors.initials: A
authors.lastname: Fernández-Navarro
authors.forename: Jordi
authors.initials: J
authors.lastname: Niubó
authors.forename: Lucia
authors.initials: L
authors.lastname: Ortega
authors.forename: Elena
authors.initials: E
authors.lastname: Muñez-Rubio
authors.forename: María P
authors.initials: MP
authors.lastname: Romero-Gómez
authors.forename: Jordi
authors.initials: J
authors.lastname: Carratalà
mesh_terms: D000328:Adult; D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology / Q000821:virology; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009305:Nasopharynx / Q000382:microbiology / Q000821:virology; D011014:Pneumonia / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D062606:Tertiary Care Centers / Q000706:statistics & numerical data; D016896:Treatment Outcome
keywords: Clinical features; Community-acquired pneumonia; Influenza A (H1N1)pdm09; Mortality; Post-pandemic period