title: The diagnostic value of specific IgE to Ara h 2 to predict peanut allergy in children is comparable to a validated and updated diagnostic prediction model.
abstract: BACKGROUND
  A diagnostic prediction model for peanut allergy in children was recently published, using 6 predictors: sex, age, history, skin prick test, peanut specific immunoglobulin E (sIgE), and total IgE minus peanut sIgE.
  
  
  OBJECTIVE
  To validate this model and update it by adding allergic rhinitis, atopic dermatitis, and sIgE to peanut components Ara h 1, 2, 3, and 8 as candidate predictors. To develop a new model based only on sIgE to peanut components.
  
  
  METHODS
  Validation was performed by testing discrimination (diagnostic value) with an area under the receiver operating characteristic curve and calibration (agreement between predicted and observed frequencies of peanut allergy) with the Hosmer-Lemeshow test and a calibration plot. The performance of the (updated) models was similarly analyzed.
  
  
  RESULTS
  Validation of the model in 100 patients showed good discrimination (88%) but poor calibration (P < .001). In the updating process, age, history, and additional candidate predictors did not significantly increase discrimination, being 94%, and leaving only 4 predictors of the original model: sex, skin prick test, peanut sIgE, and total IgE minus sIgE. When building a model with sIgE to peanut components, Ara h 2 was the only predictor, with a discriminative ability of 90%. Cutoff values with 100% positive and negative predictive values could be calculated for both the updated model and sIgE to Ara h 2. In this way, the outcome of the food challenge could be predicted with 100% accuracy in 59% (updated model) and 50% (Ara h 2) of the patients.
  
  
  CONCLUSIONS
  Discrimination of the validated model was good; however, calibration was poor. The discriminative ability of Ara h 2 was almost comparable to that of the updated model, containing 4 predictors. With both models, the need for peanut challenges could be reduced by at least 50%.
authors.affiliation: Department of (Paediatric) Dermatology and Allergology, University Medical Center Utrecht, Utrecht, The Netherlands. r.j.b.klemans-3@umcutrecht.nl
authors.forename: Rob J B
authors.initials: RJ
authors.lastname: Klemans
authors.forename: Dianne
authors.initials: D
authors.lastname: Otte
authors.forename: Mirjam
authors.initials: M
authors.lastname: Knol
authors.forename: Edward F
authors.initials: EF
authors.lastname: Knol
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Meijer
authors.forename: Frits H J
authors.initials: FH
authors.lastname: Gmelig-Meyling
authors.forename: Carla A F M
authors.initials: CA
authors.lastname: Bruijnzeel-Koomen
authors.forename: André C
authors.initials: AC
authors.lastname: Knulst
authors.forename: Suzanne G M A
authors.initials: SG
authors.lastname: Pasmans
mesh_terms: D055516:2S Albumins, Plant / Q000276:immunology*; D052179:Antigens, Plant / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D008962:Models, Theoretical; D021183:Peanut Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D011379:Prognosis; D012372:ROC Curve; D015203:Reproducibility of Results
chemical_list: D055516:2S Albumins, Plant; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D006023:Glycoproteins; D007073:Immunoglobulin E