title: Clinical characteristics and risk factors of severe respiratory syncytial virus-associated acute lower respiratory tract infections in hospitalized infants.
abstract: BACKGROUND
  To investigate the clinical characteristics and analyze risk factors for severe respiratory syncytial virus (RSV) infection in hospitalized infants with acute lower respiratory tract infections (ALRIs).
  
  
  METHODS
  A retrospective review of the medical records of infants with RSV-associated ALRIs between March 1st, 2011 and February 29th, 2012 was conducted. Subjects were followed up over the phone or by outpatient visit six and twelve months after discharge.
  
  
  RESULTS
  Among 913 RSV-associated ALRIs infants, 288 (31.5%) had severe infections, which accounted for 4.2% of hospitalized children. The hospital RSV mortality rate was 1.0%. The proportions of cases with tachypnea, apnea, cyanosis, and fine rales were significantly higher in the severe ALRIs group (all P<0.001). Multivariate logistic regression showed that low-birth-weight [1.698 (1.028-2.805)], age less than 3 months old [3.385 (2.174-5.271)], congenital heart disease [1.667 (1.149-2.418)], bronchopulmonary dysplasia [8.505 (1.731-41.780)], and airway abnormalities [2.246 (1.008-5.005)] were independent risk factors for severe ALRIs. The incidence of bronchitis, pneumonia and readmission in the severe group was significantly higher than that of the non-severe group during the one-year follow-up (all P<0.001).
  
  
  CONCLUSIONS
  Younger age, low birth weight and underlying disease are associated with severe RSVassociated ALRIs. Furthermore, severe RSV infections may be associated with a higher frequency of subsequent bronchitis, pneumonia and re-hospitalization in the following year.
authors.affiliation: Department of Respiratory Medicine, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, China.
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Zhang
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Liu
authors.forename: Li-Ling
authors.initials: LL
authors.lastname: Qian
authors.forename: Gao-Li
authors.initials: GL
authors.lastname: Jiang
authors.forename: Chuan-Kai
authors.initials: CK
authors.lastname: Wang
authors.forename: Pin
authors.initials: P
authors.lastname: Jia
authors.forename: Peng
authors.initials: P
authors.lastname: Shi
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: Wang
mesh_terms: D000208:Acute Disease; D002673:Child, Hospitalized; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index