title: Risk factors in children hospitalized with RSV bronchiolitis versus non-RSV bronchiolitis.
abstract: BACKGROUND
  The trends in hospitalization rates and risk factors for severe bronchiolitis have not been recently described, especially after the routine implementation of prophylaxis for respiratory syncytial virus (RSV) infections.
  
  
  OBJECTIVE
  To define the burden of hospitalizations related to RSV and non-RSV bronchiolitis in a tertiary-care children's hospital from 2002 to 2007 and to identify the risk factors associated with severe disease.
  
  
  METHODS
  Medical records of patients hospitalized for bronchiolitis were reviewed for demographic, clinical, microbiologic, and radiologic characteristics as well as the presence of underlying medical conditions. Differences were evaluated between children with RSV and non-RSV bronchiolitis, and multivariable logistic regression analyses were performed to identify independent risk factors for severe disease.
  
  
  RESULTS
  Bronchiolitis hospitalizations in children younger than 2 years old (n = 4800) significantly increased from 536 (3.3%) in 2002 to 1241 (5.5%) in 2007, mainly because of RSV infections. Patients with RSV bronchiolitis (n = 2840 [66%]) were younger at hospitalization and had a lower percentage of underlying medical conditions than children hospitalized with non-RSV bronchiolitis (27 vs 37.5%; P < .001). However, disease severity defined by length of hospitalization and requirement of supplemental oxygen, intensive care, and mechanical ventilation was significantly worse in children with RSV bronchiolitis. RSV infection and prematurity, regardless of the etiology, were identified as independent risk factors for severe bronchiolitis.
  
  
  CONCLUSIONS
  There was a significant increase in hospitalizations for RSV bronchiolitis from 2002 to 2007. A majority of the children with RSV bronchiolitis were previously healthy, but their disease severity was worse compared with those hospitalized with non-RSV bronchiolitis.
authors.affiliation: Department of Pediatrics, Division of Pediatric Infectious Diseases, University of Texas Southwestern Medical Center, Texas, USA.
authors.forename: Carla G
authors.initials: CG
authors.lastname: García
authors.forename: Rafia
authors.initials: R
authors.lastname: Bhore
authors.forename: Alejandra
authors.initials: A
authors.lastname: Soriano-Fallas
authors.forename: Margaret
authors.initials: M
authors.lastname: Trost
authors.forename: Rebecca
authors.initials: R
authors.lastname: Chason
authors.forename: Octavio
authors.initials: O
authors.lastname: Ramilo
authors.forename: Asuncion
authors.initials: A
authors.lastname: Mejias
mesh_terms: D000914:Antibodies, Viral / Q000032:analysis; D001988:Bronchiolitis / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007902:Length of Stay / Q000639:trends; D008297:Male; D018357:Respiratory Syncytial Virus Infections / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D012136:Respiratory Syncytial Viruses / Q000276:immunology; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013781:Texas / Q000453:epidemiology
chemical_list: D000914:Antibodies, Viral