title: Hospital length-of-stay is associated with rhinovirus etiology of bronchiolitis.
abstract: OBJECTIVE
  To determine whether hospital length-of-stay (LOS) for bronchiolitis is influenced by the causative virus: respiratory syncytial virus (RSV) or rhinovirus.
  
  
  METHODS
  This prospective study was carried out in 3 university hospitals in Finland during 2 consecutive winter seasons. We enrolled consecutive children <2 years of age hospitalized with an attending physician's diagnosis of bronchiolitis. All enrolled children were included in the primary analysis. A parallel analysis was also conducted using a stricter definition for bronchiolitis (age <12 months and no history of wheeze). Polymerase chain reaction was used to test the nasopharyngeal aspirate samples for multiple respiratory pathogens.
  
  
  RESULTS
  The median age of the 408 children was 8 months, 73% had no history of wheeze and their median hospital LOS was 2 days. 144 (35%) children had RSV only and 92 (23%) children rhinovirus only infections. Children with rhinovirus only had shorter duration of prehospital symptoms, higher disease severity score at entry and more often a history of wheezing (all P ≤ 0.001). Controlling for 7 demographic and clinical characteristics, those with rhinovirus only had shorter hospital LOS when compared with children with RSV only (adjusted odds ratio: 0.45; 95% confidence interval: 0.22-0.92; P = 0.03). The rhinovirus only finding was similar in the subset of 206 children with stricter diagnosis (adjusted odds ratio: 0.30; 0.06-1.49; P = 0.14).
  
  
  CONCLUSIONS
  Hospital LOS is associated with rhinovirus etiology of bronchiolitis. Our data call attention to the importance of both RSV and rhinovirus testing in clinical research.
authors.affiliation: From the *Department of Pediatrics, Turku University Hospital, Turku, Finland; †Department of Medicine, Boston Children's Hospital, Boston, MA; ‡Departments of Molecular Virology and Microbiology, and Pediatrics, Baylor College of Medicine, Houston, TX; §Department of Pediatrics, Kuopio University Hospital, Kuopio; ¶Department of Pediatrics, Tampere University Hospital, Tampere, Finland; and ‖Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA; **Allergy Unit, Tampere University Hospital, Tampere, Finland.
authors.forename: Tuomas
authors.initials: T
authors.lastname: Jartti
authors.forename: Matilda
authors.initials: M
authors.lastname: Aakula
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Mansbach
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Piedra
authors.forename: Eija
authors.initials: E
authors.lastname: Bergroth
authors.forename: Petri
authors.initials: P
authors.lastname: Koponen
authors.forename: Juho E
authors.initials: JE
authors.lastname: Kivistö
authors.forename: Ashley F
authors.initials: AF
authors.lastname: Sullivan
authors.forename: Janice A
authors.initials: JA
authors.lastname: Espinola
authors.forename: Sami
authors.initials: S
authors.lastname: Remes
authors.forename: Matti
authors.initials: M
authors.lastname: Korppi
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D001988:Bronchiolitis / Q000821:virology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007902:Length of Stay; D008297:Male; D010850:Picornaviridae Infections / Q000503:physiopathology* / Q000821:virology*; D011446:Prospective Studies; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification*; D012229:Rhinovirus / Q000302:isolation & purification*