title: Asthma severity scores for preschoolers displayed weaknesses in reliability, validity, and responsiveness.
abstract: OBJECTIVE
  To evaluate the measurement properties of asthma severity scores for use in preschool children.
  
  
  METHODS
  A Medline search was used to identify published asthma severity scores for use in preschool children. The measurement properties of the scores (item development, reliability, validity, responsiveness, and usability) were evaluated using a published framework.
  
  
  RESULTS
  Ten asthma severity scores were identified, with 19 different clinical variables used as items. Interrater agreement was assessed by five scores. Only two scores--Clinical Asthma Score (CAS) and Respiratory Distress Assessment Index (RDAI)--reported good agreement based on weighted kappa-statistics (0.64-0.90). Construct validity was reported by the CAS, Clinical Asthma Evaluation Score (CAES), the Clinical Symptom Grading System (CSGS), and the Preschool Respiratory Assessment Measure (PRAM). Correlation coefficients between asthma severity scores and clinical measures (length of stay, drug dosing interval, O2 saturation, health professional assessment, PaO2, PaCO2) ranged from 0.47 to 0.70. Responsiveness was formally demonstrated for two scales (PRAM, CAS).
  
  
  CONCLUSIONS
  Most asthma severity scales for use in preschool children have been informally developed. Recently developed scores (CAS, PRAM) have more rigorously evaluated their measurement properties. Research is needed to directly compare the asthma severity scores developed for use in preschool children.
authors.affiliation: Division of Paediatric Medicine, Paediatric Outcomes Research Team, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8 Canada. catherine.birken@sickkids.ca
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Birken
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Parkin
authors.forename: Colin
authors.initials: C
authors.lastname: Macarthur
mesh_terms: D001249:Asthma / Q000503:physiopathology*; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D008168:Lung / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index