title: Information on co-morbidities collected by history is useful for assigning Otitis Media risk to children.
abstract: OBJECTIVE
  Determine if a 2-Step multivariate analysis of historical symptom/sign data for comorbid diseases can abstract high-level constructs useful in assigning a child's "risk" for different Otitis Media expressions.
  
  
  METHODS
  Seventeen items related to the symptom/sign expression of hypothesized Otitis Media comorbidities were collected by history on 141 3-year-old children. Using established criteria, the children were assigned to 1 of 3 groups: Control (no significant past Otitis Media, n=45), Chronic Otitis Media with Effusion (n=45) and Recurrent Acute Otitis Media (n=51). Principal Component Analysis was used to identify factors representing the non-redundant shared information among related items and Discriminant Analysis operating on those factors was used to estimate the best predictor equation for pairwise group assignments.
  
  
  RESULTS
  Six multivariate factors representing the assignable comorbidities of frequent colds, nasal allergy, gastroesophageal disease (specific and general), nasal congestion and asthma were identified and explained 81% of the variance in the 17 items. Discriminant Analysis showed that, for the Control-Chronic Otitis Media with Effusion comparison, a combination of 3 factors and, for the Control-Recurrent Acute Otitis Media comparison, a combination of 2 factors had assignment accuracies of 74% and 68%, respectively. For the contrast between the two disease expressions, a 2-factor combination had an assignment accuracy of 61%.
  
  
  CONCLUSIONS
  These results show that this analytic methodology can abstract high-level constructs, comorbidities, from low-level data, symptom/sign scores, support a linkage between certain comorbidities and Otitis Media risk and suggest that specific comorbidity combinations contain information relevant to assigning the risk for different Otitis Media expressions.
authors.affiliation: University of Pittsburgh School of Medicine, Department of Otolaryngology, Pittsburgh, PA, USA. Electronic address: Margaretha.Casselbrant@chp.edu.
authors.forename: Margaretha L
authors.initials: ML
authors.lastname: Casselbrant
authors.affiliation: University of Pittsburgh School of Medicine, Department of Otolaryngology, Pittsburgh, PA, USA; Division of Pediatric Otolaryngology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA.
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Mandel
authors.affiliation: University of Pittsburgh School of Medicine, Department of Otolaryngology, Pittsburgh, PA, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Doyle
mesh_terms: D000208:Acute Disease; D001249:Asthma / Q000453:epidemiology*; D002675:Child, Preschool; D002908:Chronic Disease; D003139:Common Cold / Q000453:epidemiology*; D015897:Comorbidity; D016002:Discriminant Analysis; D005260:Female; D005764:Gastroesophageal Reflux / Q000453:epidemiology*; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D015508:Nasal Obstruction / Q000453:epidemiology*; D010033:Otitis Media / Q000453:epidemiology*; D010034:Otitis Media with Effusion / Q000453:epidemiology; D025341:Principal Component Analysis; D012008:Recurrence; D065631:Rhinitis, Allergic / Q000453:epidemiology*; D018570:Risk Assessment
keywords: Children; Multivariate analysis; Otitis Media; Risk factors