title: Hospitalizations for severe lower respiratory tract infections.
abstract: BACKGROUND
  Hospitalization for lower respiratory tract infections (LRTIs) among children have been well characterized. We characterized hospitalizations for severe LRTI among children.
  
  
  METHODS
  We analyzed claims data from commercial and Medicaid insurance enrollees (MarketScan) ages 0 to 18 years from 2007 to 2011. LRTI hospitalizations were identified by the first 2 listed International Classification of Diseases, Ninth Revision discharge codes; those with ICU admission and/or receiving mechanical ventilation were defined as severe LRTI. Underlying conditions were determined from out- and inpatient discharge codes in the preceding year. We report insurance specific and combined rates that used both commercial and Medicaid rates and adjusted for age and insurance status.
  
  
  RESULTS
  During 2007-2011, we identified 16797 and 12053 severe LRTI hospitalizations among commercial and Medicaid enrollees, respectively. The rates of severe LRTI hospitalizations per 100000 person-years were highest in children aged <1 year (commercial: 244; Medicaid: 372, respectively), and decreased with age. Among commercial enrollees, ≥ 1 condition increased the risk for severe LRTI (1 condition: adjusted relative risk, 2.68; 95% confidence interval, 2.58-2.78; 3 conditions: adjusted relative risk, 4.85; 95% confidence interval, 4.65-5.07) compared with children with no medical conditions. Using commercial/Medicaid combined rates, an estimated 31289 hospitalizations for severe LRTI occurred each year in children in the United States.
  
  
  CONCLUSIONS
  Among children, the burden of hospitalization for severe LRTI is greatest among children aged <1 year. Children with underlying medical conditions are at greatest risk for severe LRTI hospitalization.
authors.affiliation: Influenza Division, National Center for Immunizations and Respiratory Diseases, Epidemic Intelligence Service assigned to the Influenza Division.
authors.forename: Adena H
authors.initials: AH
authors.lastname: Greenbaum
authors.affiliation: Influenza Division, National Center for Immunizations and Respiratory Diseases.
authors.forename: Jufu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Influenza Division, National Center for Immunizations and Respiratory Diseases.
authors.forename: Carrie
authors.initials: C
authors.lastname: Reed
authors.affiliation: Division of Environmental Hazards and Health Effects, National Center for Environmental Health.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Beavers
authors.affiliation: Division for Heart Disease and Stroke Prevention, National Center for Chronic Disease Prevention and Health Promotion, and.
authors.forename: David
authors.initials: D
authors.lastname: Callahan
authors.affiliation: Division of Birth Defects and Developmental Disabilities, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia.
authors.forename: Deborah
authors.initials: D
authors.lastname: Christensen
authors.affiliation: Influenza Division, National Center for Immunizations and Respiratory Diseases.
authors.forename: Lyn
authors.initials: L
authors.lastname: Finelli
authors.affiliation: Influenza Division, National Center for Immunizations and Respiratory Diseases, afry@cdc.gov.
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Fry
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual / Q000639:trends; D005260:Female; D006760:Hospitalization / Q000639:trends*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008484:Medicaid / Q000639:trends*; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology
keywords: children; hospitalizations; severe respiratory tract infection