title: Clinical risk factors are more relevant than respiratory viruses in predicting bronchiolitis severity.
abstract: BACKGROUND
  The role of respiratory viruses in the pathogenesis of bronchiolitis was re-evaluated with the use of molecular methods such as PCR for virus detection. Whether specific viruses or the classical clinical risk factors are more important in determining severe bronchiolitis is not well established.
  
  
  OBJECTIVE
  To analyze the specific viruses and clinical variables that can predict severe bronchiolitis at admission.
  
  
  METHODS
  Nasopharyngeal aspirates were prospectively collected from 484 children <12 months admitted to the pediatrics ward or PICU at Universitary Hospital Sant Joan de Déu (Barcelona, Spain) for bronchiolitis from October 2007 to October 2008. Clinical and demographic data were collected. Sixteen respiratory viruses were studied using PCR. Severity was assessed with a bronchiolitis clinical score (BCS).
  
  
  RESULTS
  Four hundred ten infants that tested positive for respiratory viruses were analyzed. Mixed viral infections did not increase the severity of the disease. Rhinovirus was associated with severe BCS in univariate analysis (P = 0.041), but in the multivariate logistic regression including viruses and clinical data only bronchopulmonary dysplasia (OR 7.2; 95% CI 1.2-43.3), congenital heart disease (OR 4.7; 95% CI 1.1-19.9), prematurity (OR 2.6; 95% CI 1.3-5.1), and fever (OR 1.8, 95% CI 1.1-3.1) showed statistical significance for predicting severe BCS.
  
  
  CONCLUSIONS
  Classical clinical risk factors have more weight in predicting a severe BCS in infants with acute bronchiolitis than the involved viruses.
authors.affiliation: Department of Pediatrics, Hospital Universitari Sant Joan de Déu, Barcelona, Spain. sricart@hsjdbcn.org
authors.forename: Silvia
authors.initials: S
authors.lastname: Ricart
authors.forename: Maria Angeles
authors.initials: MA
authors.lastname: Marcos
authors.forename: Marta
authors.initials: M
authors.lastname: Sarda
authors.forename: Andres
authors.initials: A
authors.lastname: Anton
authors.forename: Carmen
authors.initials: C
authors.lastname: Muñoz-Almagro
authors.forename: Tomas
authors.initials: T
authors.lastname: Pumarola
authors.forename: Marti
authors.initials: M
authors.lastname: Pons
authors.forename: Juan Jose
authors.initials: JJ
authors.lastname: Garcia-Garcia
mesh_terms: D001988:Bronchiolitis / Q000453:epidemiology* / Q000821:virology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016133:Polymerase Chain Reaction; D012307:Risk Factors; D012720:Severity of Illness Index