title: [Predictive factors for pneumonia in adults infected with the new pandemic A (H1H1) influenza virus].
abstract: BACKGROUND
  On April 2009 a new A (H1N1) influenza virus was identified with a higher incidence of severe outcome in younger people, most of them with pneumonia. The objective of our study was to identify the predictive risk factors of pneumonia in patients with the new A (H1N1) influenza virus infection.
  
  
  METHODS
  Prospective cohort study of adults infected with the new A (H1N1) influenza virus, admitted in a universitary hospital, from june 2009 to January 2010. Pneumonia was defined as the presence of any pulmonary infiltrate of any distribution with no other evident cause, in the chest radiography. A comparative analysis was made with patients with A (H1N1) influenza without pneumonia.
  
  
  RESULTS
  281 patients with influenza A (H1N1) were treated. Thirty of them (10.6%) had pneumonia and 11 (3.9%) required intensive care. The global mortality was 0.7%. For the comparative analysis, 42 patients with influenza A (H1N1) without pneumonia were analysed (20 hospitalized and 22 nonhospitalised). In the multivariate analysis, obesity (BMI>30), (OR: 3.8; IC 95%: 0.99-15.0), time since symptom onset until hospital admission (OR 1.34; IC 95% 1.04-1.72), serum C reactive protein levels (OR:1.10; IC 95%: 0.98-1.24) and serum IgG2 levels (OR:1.08; IC 95%: 1.0- 1.01), were identified as independent risk factors for pneumonia.
  
  
  CONCLUSIONS
  Obesity, delay in medical care and higher levels of C reactive protein and IgG2 were predictive factors for pneumonia in adult patients with A (H1N1) influenza infection.
authors.affiliation: Servicio de Medicina Interna-Enfermedades Infecciosas, Hospital del Mar, Barcelona, Spain.
authors.forename: Elisabet Lerma
authors.initials: EL
authors.lastname: Chippirraz
authors.forename: Lluisa
authors.initials: L
authors.lastname: Sorlí
authors.forename: Milagro
authors.initials: M
authors.lastname: Montero
authors.forename: Virgina
authors.initials: V
authors.lastname: Mas
authors.forename: Eduardo López
authors.initials: EL
authors.lastname: Granados
authors.forename: Carles
authors.initials: C
authors.lastname: Vilaplana
authors.forename: Francisco
authors.initials: F
authors.lastname: Alvarez-Lerma
authors.forename: Hernando
authors.initials: H
authors.lastname: Knobel
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Horcajada
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001774:Blood Chemical Analysis; D001784:Blood Gas Analysis; D002097:C-Reactive Protein / Q000032:analysis; D015331:Cohort Studies; D057210:Delayed Diagnosis; D005260:Female; D006760:Hospitalization; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications* / Q000821:virology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000453:epidemiology; D011024:Pneumonia, Viral / Q000000981:diagnostic imaging / Q000209:etiology* / Q000821:virology; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011859:Radiography; D012307:Risk Factors; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G; D002097:C-Reactive Protein