title: Trends in respiratory syncytial virus bronchiolitis hospitalizations in children less than 1 year: 2004-2012.
abstract: OBJECTIVE
  To analyze trends in health outcomes and the influence of risk factors in children under 1 year with acute bronchiolitis due to respiratory syncytial virus (RSV bronchiolitis). A risk-adjustment model for RSV bronchiolitis in-hospital mortality was also developed.
  
  
  METHODS
  Retrospective study of hospitalizations for RSV bronchiolitis in children aged <1 year from 2004 to 2012. We used nationally representative data from the Spanish National Health Service records.
  
  
  RESULTS
  Over the study period, the annual hospital discharges for RSV bronchiolitis ranged between 6390 and 8637. The annual in-hospital mortality rate ranged from 120 (2004) to 69 (2012) per 100,000 hospitalizations and the mean length of stay decreased steadily from 6.5 to 5.2 days (p < 0.001); 98.3% of hospitalizations for RSV bronchiolitis were children without risk factors. The in-hospital mortality rate due to RSV bronchiolitis in children with risk factors was 18.8 times higher than non-high-risk children and, in adjusted analyses, the OR of in-hospital mortality due to RSV bronchiolitis was higher than that due to other causes.
  
  
  CONCLUSIONS
  This study is a retrospective analysis, based on administrative data. It does not include data about pre- or in-hospital treatments, and has the limitations inherent in procedures for determining risk-adjusted mortality rates. Socioeconomic and environmental factors have not been considered in this study.
  
  
  CONCLUSIONS
  RSV bronchiolitis is a leading cause of hospitalizations for infants under 1 year and has not shown incidence reduction over a 9 year period. Risk factors increase the in-hospital mortality risk and it is higher if the hospitalization cause is RSV bronchiolitis than any other reason.
authors.affiliation: a Department of Neonatology , Gregorio Marañon Hospital , Madrid , Spain ;
authors.forename: Manuel
authors.initials: M
authors.lastname: Sanchez-Luna
authors.affiliation: b Institute Foundation for the Improvement of Health Care , Madrid , Spain ;
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Elola
authors.affiliation: b Institute Foundation for the Improvement of Health Care , Madrid , Spain ;
authors.forename: Cristina
authors.initials: C
authors.lastname: Fernandez-Perez
authors.affiliation: c Control Management Service , 12 de Octubre Hospital , Madrid , Spain.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Bernal
authors.affiliation: b Institute Foundation for the Improvement of Health Care , Madrid , Spain ;
authors.forename: Adriana
authors.initials: A
authors.lastname: Lopez-Pineda
mesh_terms: D000208:Acute Disease; D001988:Bronchiolitis / Q000453:epidemiology* / Q000821:virology*; D003625:Data Collection; D017052:Hospital Mortality; D006760:Hospitalization / Q000639:trends*; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007902:Length of Stay; D008962:Models, Theoretical; D010359:Patient Readmission; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology*; D012136:Respiratory Syncytial Viruses; D012189:Retrospective Studies; D012307:Risk Factors; D012923:Social Class; D013030:Spain
keywords: Bronchiolitis; In-hospital mortality; Readmission; Respiratory syncytial virus